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Sample records for ground motion systhesis

  1. Deep Borehole Instrumentation Along San Francisco Bay Bridges: 1996 - 2003 and Strong Ground Motion Systhesis Along the San Francisco/Oakland Bay Bridge

    SciTech Connect

    Hutchings, L; Foxall, W; Kasameyer, P; larsen, S; Hayek, C; Tyler-Turpin, C; Aquilino, J; Long, L

    2005-04-22

    As a result of collaboration between the Berkeley Seismographic Station, Lawrence Livermore National Laboratory, and Caltrans, instrument packages have been placed in bedrock in six boreholes and two surface sites along the San Francisco/Oakland Bay Bridge. Since 1996 over 200 local earthquakes have been recorded. Prior to this study few seismic recording instruments existed in bed-rock in San Francisco Bay. We utilized the data to perform analysis of ground motion variability, wave passage, site response, and up-and down-hole wave propagation along the Bay Bridge. We also synthesized strong ground motion at nine locations along the Bay Bridge. Key to these studies is LLNL's effort to exploit the information available in weak ground motions (generally from earthquakes < M=4.0) to enhance predictions of seismic hazards. We found that Yerba Island has no apparent site response at the surface relative to a borehole site. The horizontal to vertical spectral ratio method best revealed no site response, while the complex signal spectral ratio method had the lowest variance for spectral ratios and best predicted surface recordings when the borehole recording was used as input. Both methods identified resonances at about the same frequencies. Regional attenuation results in a significant loss of high frequencies in both surface and borehole recordings. Records are band limited at near 3 Hz. Therefore a traditional rock outcrop site response, flat to high frequency in displacement, is not available. We applied a methodology to predict and synthesize strong ground motion along the San Francisco/Oakland Bay Bridge from a M=7.25 earthquake along the Hayward fault, about12 km distant. We synthesized for three-components and broad-band (0.0-25.0 Hz) ground motion accelerations, velocities, and displacements. We examined two different possible rupture scenarios, a ''mean'' and ''one standard deviation'' model. We combined the high frequency calculations (Hz > 0.7) based on

  2. Stochastic ground motion simulation

    USGS Publications Warehouse

    Rezaeian, Sanaz; Xiaodan, Sun

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  3. Wind-induced ground motion

    NASA Astrophysics Data System (ADS)

    Naderyan, Vahid; Hickey, Craig J.; Raspet, Richard

    2016-02-01

    Wind noise is a problem in seismic surveys and can mask the seismic signals at low frequency. This research investigates ground motions caused by wind pressure and shear stress perturbations on the ground surface. A prediction of the ground displacement spectra using the measured ground properties and predicted pressure and shear stress at the ground surface is developed. Field measurements are conducted at a site having a flat terrain and low ambient seismic noise. Triaxial geophones are deployed at different depths to study the wind-induced ground vibrations as a function of depth and wind velocity. Comparison of the predicted to the measured wind-induced ground displacement spectra shows good agreement for the vertical component but significant underprediction for the horizontal components. To validate the theoretical model, a test experiment is designed to exert controlled normal pressure and shear stress on the ground using a vertical and a horizontal mass-spring apparatus. This experiment verifies the linear elastic rheology and the quasi-static displacements assumptions of the model. The results indicate that the existing surface shear stress models significantly underestimate the wind shear stress at the ground surface and the amplitude of the fluctuation shear stress must be of the same order of magnitude as the normal pressure. Measurement results show that mounting the geophones flush with the ground provides a significant reduction in wind noise on all three components of the geophone. Further reduction in wind noise with depth of burial is small for depths up to 40 cm.

  4. Estimation of ground motion parameters

    USGS Publications Warehouse

    Boore, David M.; Oliver, Adolph A., III; Page, Robert A.; Joyner, William B.

    1978-01-01

    Strong motion data from western North America for earthquakes of magnitude greater than 5 are examined to provide the basis for estimating peak acceleration, velocity, displacement, and duration as a function of distance for three magnitude classes. Data from the San Fernando earthquake are examined to assess the effects of associated structures and of geologic site conditions on peak recorded motions. Small but statistically significant differences are observed in peak values of horizontal acceleration, velocity, and displacement recorded on soil at the base of small structures compared with values recorded at the base of large structures. Values of peak horizontal acceleration recorded at soil sites in the San Fernando earthquake are not significantly different from the values recorded at rock sites, but values of peak horizontal velocity and displacement are significantly greater at soil sites than at rock sites. Three recently published relationships for predicting peak horizontal acceleration are compared and discussed. Considerations are reviewed relevant to ground motion predictions at close distances where there are insufficient recorded data points.

  5. Recent ground motion studies at Fermilab

    SciTech Connect

    Shiltsev, V.; Volk, J.; Singatulin, S.; /Novosibirsk, IYF

    2009-04-01

    Understanding slow and fast ground motion is important for the successful operation and design for present and future colliders. Since 2000 there have been several studies of ground motion at Fermilab. Several different types of HLS (hydro static level sensors) have been used to study slow ground motion (less than 1 hertz) seismometers have been used for fast (greater than 1 hertz) motions. Data have been taken at the surface and at locations 100 meters below the surface. Data of recent slow ground motion measurements with HLSs, many years of alignment data and results of the ATL-analysis are presented and discussed.

  6. Estimation of ground motion parameters

    USGS Publications Warehouse

    Boore, David M.; Joyner, W.B.; Oliver, A.A.; Page, R.A.

    1978-01-01

    Strong motion data from western North America for earthquakes of magnitude greater than 5 are examined to provide the basis for estimating peak acceleration, velocity, displacement, and duration as a function of distance for three magnitude classes. A subset of the data (from the San Fernando earthquake) is used to assess the effects of structural size and of geologic site conditions on peak motions recorded at the base of structures. Small but statistically significant differences are observed in peak values of horizontal acceleration, velocity and displacement recorded on soil at the base of small structures compared with values recorded at the base of large structures. The peak acceleration tends to b3e less and the peak velocity and displacement tend to be greater on the average at the base of large structures than at the base of small structures. In the distance range used in the regression analysis (15-100 km) the values of peak horizontal acceleration recorded at soil sites in the San Fernando earthquake are not significantly different from the values recorded at rock sites, but values of peak horizontal velocity and displacement are significantly greater at soil sites than at rock sites. Some consideration is given to the prediction of ground motions at close distances where there are insufficient recorded data points. As might be expected from the lack of data, published relations for predicting peak horizontal acceleration give widely divergent estimates at close distances (three well known relations predict accelerations between 0.33 g to slightly over 1 g at a distance of 5 km from a magnitude 6.5 earthquake). After considering the physics of the faulting process, the few available data close to faults, and the modifying effects of surface topography, at the present time it would be difficult to accept estimates less than about 0.8 g, 110 cm/s, and 40 cm, respectively, for the mean values of peak acceleration, velocity, and displacement at rock sites

  7. Ground Motion Modeling in the Eastern Caucasus

    NASA Astrophysics Data System (ADS)

    Pitarka, Arben; Gok, Rengin; Yetirmishli, Gurban; Ismayilova, Saida; Mellors, Robert

    2016-05-01

    In this study, we analyzed the performance of a preliminary three-dimensional (3D) velocity model of the Eastern Caucasus covering most of the Azerbaijan. The model was developed in support to long-period ground motion simulations and seismic hazard assessment from regional earthquakes in Azerbaijan. The model's performance was investigated by simulating ground motion from the damaging Mw 5.9, 2012 Zaqatala earthquake, which was well recorded throughout the region by broadband seismic instruments. In our simulations, we use a parallelized finite-difference method of fourth-order accuracy. The comparison between the simulated and recorded ground motion velocity in the modeled period range of 3-20 s shows that in general, the 3D velocity model performs well. Areas in which the model needs improvements are located mainly in the central part of the Kura basin and in the Caspian Sea coastal areas. Comparisons of simulated ground motion using our 3D velocity model and corresponding 1D regional velocity model were used to locate areas with strong 3D wave propagation effects. In areas with complex underground structure, the 1D model fails to produce the observed ground motion amplitude and duration, and spatial extend of ground motion amplification caused by wave propagation effects.

  8. Ground Motion Modeling in the Eastern Caucasus

    NASA Astrophysics Data System (ADS)

    Pitarka, Arben; Gok, Rengin; Yetirmishli, Gurban; Ismayilova, Saida; Mellors, Robert

    2016-08-01

    In this study, we analyzed the performance of a preliminary three-dimensional (3D) velocity model of the Eastern Caucasus covering most of the Azerbaijan. The model was developed in support to long-period ground motion simulations and seismic hazard assessment from regional earthquakes in Azerbaijan. The model's performance was investigated by simulating ground motion from the damaging Mw 5.9, 2012 Zaqatala earthquake, which was well recorded throughout the region by broadband seismic instruments. In our simulations, we use a parallelized finite-difference method of fourth-order accuracy. The comparison between the simulated and recorded ground motion velocity in the modeled period range of 3-20 s shows that in general, the 3D velocity model performs well. Areas in which the model needs improvements are located mainly in the central part of the Kura basin and in the Caspian Sea coastal areas. Comparisons of simulated ground motion using our 3D velocity model and corresponding 1D regional velocity model were used to locate areas with strong 3D wave propagation effects. In areas with complex underground structure, the 1D model fails to produce the observed ground motion amplitude and duration, and spatial extend of ground motion amplification caused by wave propagation effects.

  9. Recent Ground Motion Studies at SLAC

    SciTech Connect

    Seryi, Andrei

    2000-06-28

    Studies of slow ground motion have recently been performed at SLAC using the linac laser alignment system over a period of one month. Two significant effects responsible for the observed motion have been identified, namely tidal forces and variation of external atmospheric pressure. The latter is of particular interest as it may result in misalignments with rather short wavelength.

  10. Examining Rotational Ground Motion Induced by Tornados

    NASA Astrophysics Data System (ADS)

    Kessler, Elijah; Dunn, Robert

    2016-03-01

    Ring lasers are well known for their ability to detect rotation and to serve as replacements for mechanical gyroscopes. The sensitivity of large ring lasers to various forms of ground motion is less familiar. Since ring lasers preferentially measure rotational ground motion and a standard seismograph is designed to measure translational and vertical ground motion, each device responds to different aspects of ground movement. Therefore, the two instruments will be used to explore responses to microseisms, earthquake generated shear waves, and in particular tornado generated ground movement. On April 27, 2014 an EF4 tornado devastated Vilonia, AR a small town ~ 21 km from the Hendrix College ring laser. The proximity of the tornado's path to the ring laser interferometer and to a seismograph located in Vilonia provided the opportunity to examine the response of these instruments to tornadic generated ground motion. Our measurements suggest tornadic weather systems can produce both rotational and lateral ground motion. This contention is supported by an after the fact damage survey which found that the tornado flattened a forest in which trees were uprooted and laid down in a pair of converging arcs with the centerline pointed in the direction of the tornado's path.

  11. Synthetic Strong Ground Motion Validation and Prediction

    NASA Astrophysics Data System (ADS)

    Zeng, Y.

    2003-12-01

    In this paper, I first validate a ground motion simulation procedure against ground motion observation from the Imperial Valley, Loma Prieta, Landers, Northridge, Kobe, and Kocaeli earthquakes. The ground motion simulation procedure follows Zeng et al. (1994) using a composite source model. In that model, the source is taken as a superposition of circular subevents with a constant stress drop. The number of subevents and their radius follows a power law distribution equivalent to the Gutenberg and Richter's magnitude-frequency relation for seismicity. The heterogeneous nature of the composite source model is characterized by its maximum subevent size and subevent stress drop. As rupture propagates through each subevent, it radiates a circular crack rupture pulse. In addition to wave propagation through a layered earth, the model has been improved by including scattering waves from small scale heterogeneity structure of the earth, site specific ground motion prediction using weak motion site amplification, and nonlinear soil response using geotechnical engineering models. In the current validation study, the fixed and free model parameters have been systematically cataloged and the statistical distribution of those free parameters has been carefully identified. A critical component of the study is to define the function of goodness-of-fit. In this investigation I emphasize on goodness-of-fit based on ground motion response spectra. Other forms of goodness-of-fit based on seismic waveform, shake duration, accumulative energies, etc., are also examined. Based on the result, I then conduct broadband ground motion prediction from scenario earthquakes. The objective of this simulation is to argument the existing empirical strong ground motion database on magnitude, distance, and frequency range. The result will be used to test the function forms used in developing the Next-Generation-Attenuation relation initiated by PEER/SCEC/USGS.

  12. Ground Motion Prediction Models for Caucasus Region

    NASA Astrophysics Data System (ADS)

    Jorjiashvili, Nato; Godoladze, Tea; Tvaradze, Nino; Tumanova, Nino

    2016-04-01

    Ground motion prediction models (GMPMs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration or spectral acceleration because this parameter gives useful information for Seismic Hazard Assessment. Since 2003 development of Georgian Digital Seismic Network has started. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models is obtained by classical, statistical way, regression analysis. In this study site ground conditions are additionally considered because the same earthquake recorded at the same distance may cause different damage according to ground conditions. Empirical ground-motion prediction models (GMPMs) require adjustment to make them appropriate for site-specific scenarios. However, the process of making such adjustments remains a challenge. This work presents a holistic framework for the development of a peak ground acceleration (PGA) or spectral acceleration (SA) GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain.

  13. Empirical prediction of strong ground motion

    USGS Publications Warehouse

    Boore, David M.; Joyner, William B.

    1993-01-01

    In 1982, we published equations for the prediction of various measures of ground motion as a function of earthquake magnitude, distance from the earthquake rupture, and site geology. Many more strong-motion recordings have been obtained since we published our equations. The predictions of the ground motions from our published equations are in reasonable agreement with the peak accelerations from the new data. The increased number of data, however, allow us to refine our predictions for some regions of magnitude and distance space, and perhaps for other variables.

  14. Orientation-independent measures of ground motion

    USGS Publications Warehouse

    Boore, D.M.; Watson-Lamprey, Jennie; Abrahamson, N.A.

    2006-01-01

    The geometric mean of the response spectra for two orthogonal horizontal components of motion, commonly used as the response variable in predictions of strong ground motion, depends on the orientation of the sensors as installed in the field. This means that the measure of ground-motion intensity could differ for the same actual ground motion. This dependence on sensor orientation is most pronounced for strongly correlated motion (the extreme example being linearly polarized motion), such as often occurs at periods of 1 sec or longer. We propose two new measures of the geometric mean, GMRotDpp, and GMRotIpp, that are independent of the sensor orientations. Both are based on a set of geometric means computed from the as-recorded orthogonal horizontal motions rotated through all possible non-redundant rotation angles. GMRotDpp is determined as the ppth percentile of the set of geometric means for a given oscillator period. For example, GMRotDOO, GMRotD50, and GMRotD100 correspond to the minimum, median, and maximum values, respectively. The rotations that lead to GMRotDpp depend on period, whereas a single-period-independent rotation is used for GMRotIpp, the angle being chosen to minimize the spread of the rotation-dependent geometric mean (normalized by GMRotDpp) over the usable range of oscillator periods. GMRotI50 is the ground-motion intensity measure being used in the development of new ground-motion prediction equations by the Pacific Earthquake Engineering Center Next Generation Attenuation project. Comparisons with as-recorded geometric means for a large dataset show that the new measures are systematically larger than the geometric-mean response spectra using the as-recorded values of ground acceleration, but only by a small amount (less than 3%). The theoretical advantage of the new measures is that they remove sensor orientation as a contributor to aleatory uncertainty. Whether the reduction is of practical significance awaits detailed studies of large

  15. Ground motion estimation and nonlinear seismic analysis

    SciTech Connect

    McCallen, D.B.; Hutchings, L.J.

    1995-08-14

    Site specific predictions of the dynamic response of structures to extreme earthquake ground motions are a critical component of seismic design for important structures. With the rapid development of computationally based methodologies and powerful computers over the past few years, engineers and scientists now have the capability to perform numerical simulations of many of the physical processes associated with the generation of earthquake ground motions and dynamic structural response. This paper describes application of a physics based, deterministic, computational approach for estimation of earthquake ground motions which relies on site measurements of frequently occurring small (i.e. M < 3 ) earthquakes. Case studies are presented which illustrate application of this methodology for two different sites, and nonlinear analyses of a typical six story steel frame office building are performed to illustrate the potential sensitivity of nonlinear response to site conditions and proximity to the causative fault.

  16. Strong ground motion prediction using virtual earthquakes.

    PubMed

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion. PMID:24458636

  17. Ground motion: An introduction for accelerator builders

    SciTech Connect

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed.

  18. Modeling Ground Motions in Eastern Europe

    NASA Astrophysics Data System (ADS)

    Onur, Tuna; Nyst, Marleen

    2010-05-01

    As part of an overall risk modeling effort, we developed empirical models to estimate ground shaking in terms of spectral response due to different types of earthquakes in Eastern Europe. In this presentation, we will focus on the relatively high risk regions such as Vrancea seismic zone in Romania, and high seismic activity regions of Greece and Turkey. Each of these regions presents unique challenges in estimating ground motions. We provide a review of existing research on the estimation of ground motion for intermediate depth Vrancea earthquakes and propose a ground motion model to be used for this region based on spectral response. For Greece and Turkey, we review locally developed ground motion models as well as explore applicability of NGA models developed in the US. Final models that were derived out of this process are presented and discussed. We also provide a discussion of how the present study compares with our earlier models developed for the rest of Europe at the borders of the model regions.

  19. Measurement, characterization, and prediction of strong ground motion

    USGS Publications Warehouse

    Joyner, William; Boore, David M.

    1988-01-01

    A number of predictive relationships derived from regression analysis of strong-motion data are available for horizontal peak acceleration, velocity, and response spectral values. Theoretical prediction of ground motion calls for stochastic source models because source heterogeneities control the amplitude of ground motion at most, if not all, frequencies of engineering interest. Theoretical methods have been developed for estimation of ground-motion parameters and simulation of ground-motion time series. These methods are particularly helpful for regions such, as eastern North America where strong-motion data are sparse. The authors survey the field, first reviewing developments in ground-motion measurement and data processing. The authors then consider the choice of parameters for characterizing strong ground motion and describe the wave-types involved in strong ground motion and the factors affecting ground-motion amplitudes. They conclude by describing methods for predicting ground motion.

  20. Using Tremor to Predict Strong Ground Motion

    NASA Astrophysics Data System (ADS)

    Baltay, A.; Asawachaisujja, S.; Beroza, G. C.

    2012-12-01

    Due to its widespread occurrence, frequency content, and location, tectonic tremor presents an exceptional opportunity to test and improve strong ground motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual tremor events to constrain the distance attenuation relationship of peak ground acceleration (PGA) and peak ground velocity (PGV) of tremor for application to strong ground motion prediction. Ground motion prediction equations (GMPE) relate ground motion amplitude to earthquake magnitude and distance, and are critically important for creating seismic hazard maps. In practice, GMPEs are determined empirically with earthquake data, recorded at many stations. In some areas of high earthquake hazard, such as Cascadia, the data set of recorded earthquakes for ground motion prediction is extremely sparse. Tectonic tremor, however, occurs frequently and abundantly in many subduction zones, including Cascadia. Moreover, the tremor band of 1-10 Hz, corresponds precisely to the frequency band of greatest interest for engineering seismology. Finally, tremor is thought to occur at or near the down-dip limit of rupture in large megathrust earthquakes, which is the area that is likely to control high frequency shaking in large earthquakes. Tremor in Cascadia is strong enough to be recorded at borehole stations of the Plate Boundary Observatory to distances of nearly 200 km, which is sufficient to place important constraints on ground motion decay with distance. We characterize the amplitude of thousands of individual tremor events occurring nearly continuously throughout an ETS event, using tremor locations and timings from independently determined catalogs [Wech and Creager, 2008]. Because tremor bursts do not have a defined absolute magnitude, we normalize all events to a reference magnitude. PGA and PGV for tremor shows a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and

  1. The NTS Ground Motion Data Base

    SciTech Connect

    App, F.N.

    1994-04-01

    The NTS (Nevada Test Site) Ground Motion Data Base is composed of strong motion data recorded during the normal execution of the US underground test program. It contains surface, subsurface, and structure motion data as digitized waveforms. Currently the data base contains information from 148 underground explosions This represents about 4200 measurements and nearly 12,000 individual digitized waveforms. Most of the data was acquired by Los Alamos National Laboratory (LANL) in connection with LANL sponsored underground tests. Some was acquired by Los Alamos on tests conducted by the Defense Nuclear Agency (DNA) and Lawrence Livermore National Laboratory (LLNL), and there are some measurements which were acquired by the other test sponsors on their events and provided to us for inclusion in this data base. Included in the data set is the Los Alamos motion data from the Non-Proliferation Experiment (NPE).

  2. Ground motion data for International Collider models

    SciTech Connect

    Volk, J.T.; LeBrun, P.; Shiltsev, V.; Singatulin, S.; /Fermilab

    2007-11-01

    The proposed location for the International Linear Collider (ILC) in the Americas region is Fermilab in Batavia Illinois. If built at this location the tunnels would be located in the Galena Platteville shale at a depth of 100 or more meters below the surface. Studies using hydro static water levels and seismometers have been conducted in the MINOS hall and the LaFrange Mine in North Aurora Illinois to determine the level of ground motion. Both these locations are in the Galena Platteville shale and indicate the typical ground motion to be expected for the ILC. The data contains both natural and cultural noise. Coefficients for the ALT law are determined. Seismic measurements at the surface and 100 meters below the surface are presented.

  3. CHARACTERIZING EXTREME GROUND MOTIONS AT YUCCA MTN

    SciTech Connect

    W. Silva, I. Wong, J. Ake, R. Quittmeyer, and C. Costantino

    2006-02-27

    Characterization of the epistemic uncertainty and aleatory variability of ground motion, as part of the Yucca Mountain nuclear waste repository PSHA (Stepp et al., 2001), results in ground motion values that increase without bound as lower and lower annual probabilities of exceedance are considered. For probabilities of exceedance less than about 10{sup -6} (yr{sup -1}), use of these results as input to the site response model leads to ground motion values for the repository that most engineering seismologists feel are not credible. To provide a defensible technical basis to develop credible emplacement level motions for extreme events, the undeformed nature of the 12.8 million year old lithophysal tuff units at Yucca Mountain provide strong constraints on the level of strain (stress) not experienced by the site since deposition of the tuff. Uniaxial unconfined compressive tests (the only tests available to the project) of the lithophysal tuff indicate axial strains of about 0.3% at fracture, which converts to approximately 0.2% shear-strain. This shear-strain limit (fracture strain), which has not occurred, is used with standard equivalent-linear (and nonlinear) point-source site response analyses to develop corresponding response spectra assuming a controlling earthquake of M 6.5 at a distance of 5 km, based on the site PSHA. In addition to the uncertainty in fracture shear-strain resulting from unconfined uniaxial tests, the analyses demonstrate that the uncertainty in nonlinear dynamic material properties of the tuff result in a factor of two uncertainty in extreme response spectra, conditional on a value of 0.2% for the fracture strain. To reduce the large uncertainty in extreme spectra, a high pressure ({approx} 1,000 ft), large scale ({approx} 1 ft{sup 3}) test device is needed that simulates earthquake loading conditions (cyclic shear strain). The test device would give direct measures of shear fracture strain for the lithophysal tuffs as well as reliable

  4. Compression of ground-motion data

    SciTech Connect

    Long, J.W.

    1981-04-01

    Ground motion data has been recorded for many years at Nevada Test Site and is now stored on thousands of digital tapes. The recording format is very inefficient in terms of space on tape. This report outlines a method to compress the data onto a few hundred tapes while maintaining the accuracy of the recording and allowing restoration of any file to the original format for future use. For future digitizing a more efficient format is described and suggested.

  5. Ground motions and its effects in accelerator design

    SciTech Connect

    Fischer, G.E.

    1984-07-01

    This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators. (GHT)

  6. Extreme ground motions and Yucca Mountain

    USGS Publications Warehouse

    Hanks, Thomas C.; Abrahamson, Norman A.; Baker, Jack W.; Boore, David M.; Board, Mark; Brune, James N.; Cornell, C. Allin; Whitney, John W.

    2013-01-01

    Yucca Mountain is the designated site of the underground repository for the United States' high-level radioactive waste (HLW), consisting of commercial and military spent nuclear fuel, HLW derived from reprocessing of uranium and plutonium, surplus plutonium, and other nuclear-weapons materials. Yucca Mountain straddles the western boundary of the Nevada Test Site, where the United States has tested nuclear devices since the 1950s, and is situated in an arid, remote, and thinly populated region of Nevada, ~100 miles northwest of Las Vegas. Yucca Mountain was originally considered as a potential underground repository of HLW because of its thick units of unsaturated rocks, with the repository horizon being not only ~300 m above the water table but also ~300 m below the Yucca Mountain crest. The fundamental rationale for a geologic (underground) repository for HLW is to securely isolate these materials from the environment and its inhabitants to the greatest extent possible and for very long periods of time. Given the present climate conditions and what is known about the current hydrologic system and conditions around and in the mountain itself, one would anticipate that the rates of infiltration, corrosion, and transport would be very low—except for the possibility that repository integrity might be compromised by low-probability disruptive events, which include earthquakes, strong ground motion, and (or) a repository-piercing volcanic intrusion/eruption. Extreme ground motions (ExGM), as we use the phrase in this report, refer to the extremely large amplitudes of earthquake ground motion that arise at extremely low probabilities of exceedance (hazard). They first came to our attention when the 1998 probabilistic seismic hazard analysis for Yucca Mountain was extended to a hazard level of 10-8/yr (a 10-4/yr probability for a 104-year repository “lifetime”). The primary purpose of this report is to summarize the principal results of the ExGM research program

  7. Ground Motion Studies at NuMI

    SciTech Connect

    Mayda M. Velasco; Michal Szleper

    2012-02-20

    Ground motion can cause significant deterioration in the luminosity of a linear collider. Vibration of numerous focusing magnets causes continuous misalignments, which makes the beam emittance grow. For this reason, understanding the seismic vibration of all potential LC sites is essential and related efforts in many sites are ongoing. In this document we summarize the results from the studies specific to Fermilab grounds as requested by the LC project leader at FNAL, Shekhar Mishra in FY04-FY06. The Northwestern group focused on how the ground motion effects vary with depth. Knowledge of depth dependence of the seismic activity is needed in order to decide how deep the LC tunnel should be at sites like Fermilab. The measurements were made in the NuMI tunnel, see Figure 1. We take advantage of the fact that from the beginning to the end of the tunnel there is a height difference of about 350 ft and that there are about five different types of dolomite layers. The support received allowed to pay for three months of salary of Michal Szleper. During this period he worked a 100% of his time in this project. That include one week of preparation: 2.5 months of data taking and data analysis during the full period of the project in order to guarantee that we were recording high quality data. We extended our previous work and made more systematic measurements, which included detailed studies on stability of the vibration amplitudes at different depths over long periods of time. As a consequence, a better control and more efficient averaging out of the daytime variation effects were possible, and a better study of other time dependences before the actual depth dependence was obtained. Those initial measurements were made at the surface and are summarized in Figure 2. All measurements are made with equipment that we already had (two broadband seismometers KS200 from GEOTECH and DL-24 portable data recorder). The offline data analysis took advantage of the full Fourier spectra

  8. Simulation of ground motion using the stochastic method

    USGS Publications Warehouse

    Boore, D.M.

    2003-01-01

    A simple and powerful method for simulating ground motions is to combine parametric or functional descriptions of the ground motion's amplitude spectrum with a random phase spectrum modified such that the motion is distributed over a duration related to the earthquake magnitude and to the distance from the source. This method of simulating ground motions often goes by the name "the stochastic method." It is particularly useful for simulating the higher-frequency ground motions of most interest to engineers (generally, f>0.1 Hz), and it is widely used to predict ground motions for regions of the world in which recordings of motion from potentially damaging earthquakes are not available. This simple method has been successful in matching a variety of ground-motion measures for earthquakes with seismic moments spanning more than 12 orders of magnitude and in diverse tectonic environments. One of the essential characteristics of the method is that it distills what is known about the various factors affecting ground motions (source, path, and site) into simple functional forms. This provides a means by which the results of the rigorous studies reported in other papers in this volume can be incorporated into practical predictions of ground motion.

  9. Ground Motions Due to Earthquakes on Creeping Faults

    NASA Astrophysics Data System (ADS)

    Harris, R.; Abrahamson, N. A.

    2014-12-01

    We investigate the peak ground motions from the largest well-recorded earthquakes on creeping strike-slip faults in active-tectonic continental regions. Our goal is to evaluate if the strong ground motions from earthquakes on creeping faults are smaller than the strong ground motions from earthquakes on locked faults. Smaller ground motions might be expected from earthquakes on creeping faults if the fault sections that strongly radiate energy are surrounded by patches of fault that predominantly absorb energy. For our study we used the ground motion data available in the PEER NGA-West2 database, and the ground motion prediction equations that were developed from the PEER NGA-West2 dataset. We analyzed data for the eleven largest well-recorded creeping-fault earthquakes, that ranged in magnitude from M5.0-6.5. Our findings are that these earthquakes produced peak ground motions that are statistically indistinguishable from the peak ground motions produced by similar-magnitude earthquakes on locked faults. These findings may be implemented in earthquake hazard estimates for moderate-size earthquakes in creeping-fault regions. Further investigation is necessary to determine if this result will also apply to larger earthquakes on creeping faults. Please also see: Harris, R.A., and N.A. Abrahamson (2014), Strong ground motions generated by earthquakes on creeping faults, Geophysical Research Letters, vol. 41, doi:10.1002/2014GL060228.

  10. Ground Motion Prediction Equations Empowered by Stress Drop Measurement

    NASA Astrophysics Data System (ADS)

    Miyake, H.; Oth, A.

    2015-12-01

    Significant variation of stress drop is a crucial issue for ground motion prediction equations and probabilistic seismic hazard assessment, since only a few ground motion prediction equations take into account stress drop. In addition to average and sigma studies of stress drop and ground motion prediction equations (e.g., Cotton et al., 2013; Baltay and Hanks, 2014), we explore 1-to-1 relationship for each earthquake between stress drop and between-event residual of a ground motion prediction equation. We used the stress drop dataset of Oth (2013) for Japanese crustal earthquakes ranging 0.1 to 100 MPa and K-NET/KiK-net ground motion dataset against for several ground motion prediction equations with volcanic front treatment. Between-event residuals for ground accelerations and velocities are generally coincident with stress drop, as investigated by seismic intensity measures of Oth et al. (2015). Moreover, we found faster attenuation of ground acceleration and velocities for large stress drop events for the similar fault distance range and focal depth. It may suggest an alternative parameterization of stress drop to control attenuation distance rate for ground motion prediction equations. We also investigate 1-to-1 relationship and sigma for regional/national-scale stress drop variation and current national-scale ground motion equations.

  11. Portable sensor technology for rotational ground motions

    NASA Astrophysics Data System (ADS)

    Bernauer, Felix; Wassermann, Joachim; Guattari, Frédéric; Igel, Heiner

    2016-04-01

    In this contribution we present performance characteristics of a single component interferometric fiber-optic gyroscope (IFOG). The prototype sensor is provided by iXBlue, France. It is tested in the framework of the European Research Council Project, ROMY (Rotational motions - a new observable for seismology), on its applicability as a portable and field-deployable sensor for rotational ground motions. To fully explore the benefits of this new seismic observable especially in the fields of vulcanology, ocean generated noise and geophysical exploration, such a sensor has to fulfill certain requirements regarding portability, power consumption, time stamping stability and dynamic range. With GPS-synchronized time stamping and miniseed output format, data acquisition is customized for the use in seismology. Testing time stamping accuracy yields a time shift of less than 0.0001 s and a correlation coefficient of 0.99 in comparison to a commonly used data acquisition system, Reftek 120. Sensor self-noise is below 5.0 ṡ 10‑8 rads‑1Hz‑1/2 for a frequency band from 0.001 Hz to 5.0 Hz. Analysis of Allan deviation shows an angle random walk of 3.5 ṡ 10‑8 rads‑1Hz‑1/2. Additionally, the operating range diagram is shown and ambient noise analysis is performed. The sensitivity of sensor self-noise to variations in surrounding temperature and magnetic field is tested in laboratory experiments. With a power consumption of less than 10 W, the whole system (single component sensor + data acquisition) is appropriate for field use with autonomous power supply.

  12. Realistic Ground Motion Scenarios: Methodological Approach

    SciTech Connect

    Nunziata, C.; Peresan, A.; Romanelli, F.; Vaccari, F.; Zuccolo, E.; Panza, G. F.

    2008-07-08

    The definition of realistic seismic input can be obtained from the computation of a wide set of time histories, corresponding to possible seismotectonic scenarios. The propagation of the waves in the bedrock from the source to the local laterally varying structure is computed with the modal summation technique, while in the laterally heterogeneous structure the finite difference method is used. The definition of shear wave velocities within the soil cover is obtained from the non-linear inversion of the dispersion curve of group velocities of Rayleigh waves, artificially or naturally generated. Information about the possible focal mechanisms of the sources can be obtained from historical seismicity, based on earthquake catalogues and inversion of isoseismal maps. In addition, morphostructural zonation and pattern recognition of seismogenic nodes is useful to identify areas prone to strong earthquakes, based on the combined analysis of topographic, tectonic, geological maps and satellite photos. We show that the quantitative knowledge of regional geological structures and the computation of realistic ground motion can be a powerful tool for a preventive definition of the seismic hazard in Italy. Then, the formulation of reliable building codes, based on the evaluation of the main potential earthquakes, will have a great impact on the effective reduction of the seismic vulnerability of Italian urban areas, validating or improving the national building code.

  13. Proceedings: Earthquake Ground-Motion Estimation in Eastern North America

    SciTech Connect

    1988-08-01

    Experts in seismology and earthquake engineering convened to evaluate state-of-the-art methods for estimating ground motion from earthquakes in eastern North America. Workshop results presented here will help focus research priorities in ground-motion studies to provide more-realistic design standards for critical facilities.

  14. Description of ground motion data processing codes: Volume 3

    SciTech Connect

    Sanders, M.L.

    1988-02-01

    Data processing codes developed to process ground motion at the Nevada Test Site for the Weapons Test Seismic Investigations Project are used today as part of the program to process ground motion records for the Nevada Nuclear Waste Storage Investigations Project. The work contained in this report documents and lists codes and verifies the ``PSRV`` code. 39 figs.

  15. An Improved Approach for Nonstationary Strong Ground Motion Simulation

    NASA Astrophysics Data System (ADS)

    Li, Yanan; Wang, Guoxin

    2016-05-01

    A new stochastic ground motion model for generating a suite of ground motion time history with both temporal and frequency nonstationarities for specified earthquake and site characteristics is proposed based on the wavelet method. This new model is defined in terms of 6 key parameters that characterize the duration, evolving intensity, predominant frequency, bandwidth and frequency variation of the ground acceleration process. All parameters, except for peak ground acceleration (PGA), are identified manually from a database of 2444 recorded horizontal accelerations. The two-stage regression analysis method is used to investigate the inter- and intra-event residuals. For any given earthquake and site characteristics in terms of the fault mechanism, moment magnitude, Joyner and Boore distance and site shear-wave velocity, sets of the model parameters are generated and used, in turn, by the stochastic model to generate strong ground motion accelerograms, which can capture and properly embody the primary features of real strong ground motions, including the duration, evolving intensity, spectral content, frequency variation and peak values. In addition, it is shown that the characteristics of the simulated and observed response spectra are similar, and the amplitude of the simulated response spectra are in line with the predicted values from the published seismic ground motion prediction equations (SGMPE) after a systematic comparison. The proposed method can be used to estimate the strong ground motions as inputs for structural seismic dynamic analysis in engineering practice in conjunction with or instead of recorded ground motions.

  16. Ground motion input in seismic evaluation studies

    SciTech Connect

    Sewell, R.T.; Wu, S.C.

    1996-07-01

    This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. For both types of artificial motion, time histories are generated to match target spectral shapes. For comparison, empirical motions representative of those that might result from strong earthquakes in the Eastern U.S. are also considered. The study findings suggest that artificial motions resulting from typical simulation approaches (aimed at matching a given target spectrum) are generally adequate and appropriate in representing the peak-response demands that may be induced in linear structures and equipment responding to real earthquake motions. Also, given similar input Fourier energies at high-frequencies, levels of input Fourier energy at low frequencies observed for artificial motions are substantially similar to those levels noted in real earthquake motions. In addition, the study reveals specific problems resulting from the application of Western U.S. type motions for seismic evaluation of Eastern U.S. nuclear power plants.

  17. Evaluation of Nevada Test Site Ground Motion and Rock Property Data to Bound Ground Motions at the Yucca Mountain Repository

    SciTech Connect

    Hutchings, L H; Foxall, W; Rambo, J; Wagoner, J L

    2005-03-09

    Yucca Mountain licensing will require estimation of ground motions from probabilistic seismic hazard analyses (PSHA) with annual probabilities of exceedance on the order of 10{sup -6} to 10{sup -7} per year or smaller, which correspond to much longer earthquake return periods than most previous PSHA studies. These long return periods for the Yucca Mountain PSHA result in estimates of ground motion that are extremely high ({approx} 10 g) and that are believed to be physically unrealizable. However, there is at present no generally accepted method to bound ground motions either by showing that the physical properties of materials cannot maintain such extreme motions, or the energy release by the source for such large motions is physically impossible. The purpose of this feasibility study is to examine recorded ground motion and rock property data from nuclear explosions to determine its usefulness for studying the ground motion from extreme earthquakes. The premise is that nuclear explosions are an extreme energy density source, and that the recorded ground motion will provide useful information about the limits of ground motion from extreme earthquakes. The data were categorized by the source and rock properties, and evaluated as to what extent non-linearity in the material has affected the recordings. They also compiled existing results of non-linear dynamic modeling of the explosions carried out by LLNL and other institutions. They conducted an extensive literature review to outline current understanding of extreme ground motion. They also analyzed the data in terms of estimating maximum ground motions at Yucca Mountain.

  18. Evaluation of Nevada Test Site Ground Motion and Rock Property Data to Bound Ground Motions at the Yucca Mountain Repository

    SciTech Connect

    Hutchings, L J; Foxall, W; Rambo, J; Wagoner, J L

    2005-02-14

    Yucca Mountain licensing will require estimation of ground motions from probabilistic seismic hazard analyses (PSHA) with annual probabilities of exceedance on the order of 10{sup -6} to 10{sup -7} per year or smaller, which correspond to much longer earthquake return periods than most previous PSHA studies. These long return periods for the Yucca Mountain PSHA result in estimates of ground motion that are extremely high ({approx} 10 g) and that are believed to be physically unrealizable. However, there is at present no generally accepted method to bound ground motions either by showing that the physical properties of materials cannot maintain such extreme motions, or the energy release by the source for such large motions is physically impossible. The purpose of this feasibility study is to examine recorded ground motion and rock property data from nuclear explosions to determine its usefulness for studying the ground motion from extreme earthquakes. The premise is that nuclear explosions are an extreme energy density source, and that the recorded ground motion will provide useful information about the limits of ground motion from extreme earthquakes. The data were categorized by the source and rock properties, and evaluated as to what extent non-linearity in the material has affected the recordings. They also compiled existing results of non-linear dynamic modeling of the explosions carried out by LLNL and other institutions. They conducted an extensive literature review to outline current understanding of extreme ground motion. They also analyzed the data in terms of estimating maximum ground motions at Yucca Mountain.

  19. Ground motion predictions for the Grand Saline experiment. Topical report

    SciTech Connect

    Rimer, N.; Cherry, J.T.

    1982-07-01

    Finite difference calculations are used to predict the ground motion and RVP spectra from a tamped 200 pound charge of Pelletol explosive detonated in the Grand Saline Salt Dome. Computational constitutive models and material properties for the dome salt are first normalized using ground motion data from a number of nuclear and high explosive events in salt including SALMON, GNOME, and COWBOY. The ground motion predictions for Phase III of the Grand Saline experiment are then made using our best guesses for site material properties.

  20. Engineering uses of physics-based ground motion simulations

    USGS Publications Warehouse

    Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

    2014-01-01

    This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

  1. Insights into Ground-Motion Processes from Intensity Data (Invited)

    NASA Astrophysics Data System (ADS)

    Atkinson, G. M.

    2009-12-01

    Analysis of intensity data gathered from the on-line “Did You Feel It?” (DYFI) questionnaire program (Wald et al., 1999, Seism. Res. L.) provides new insights into both contemporary and historical ground-motion processes; this is particularly important for sparsely-instrumented regions. The value of the DYFI data lies in their vast quantities and large spatial coverage. With thousands to tens of thousands of respondents providing information on the felt and damage characteristics of widely-felt earthquakes, DYFI intensity data provide surprisingly high resolution of ground-motion features. The large data quantities allow techniques such as binning to be used to bring out these features in a statistically-stable way (Atkinson and Wald, 2007, Seism. Res. L.), while correlations of the statistics of DYFI intensities with instrumental ground motions provide the link between intensity and engineering ground-motion parameters (Wald et al., 1999, Earthquake Spectra). This link is largely independent of region if its dependence on earthquake magnitude and distance is taken into account (Kaka and Atkinson, 2007, BSSA). Thus DYFI data provide a valuable tool with which ground motions can be estimated, if their felt and damage effects have been reported. This is useful both for understanding contemporary events in sparsely-instrumented regions, and for re-evaluating historical events, for which only intensity data are available. By using calibrated intensity observations, a number of ground-motion processes can be investigated based on DYFI and/or historical intensity data. For example, intensity data shed light on source scaling issues, and whether source parameters vary regionally. They can also be used to document regional attenuation features, such as the attenuation rate and its variation with distance (Atkinson and Wald, 2007). A key uncertainty in these investigations concerns the effect of spectral shape on intensity; the spectral shape is influenced by site

  2. Strong ground motions generated by earthquakes on creeping faults

    USGS Publications Warehouse

    Harris, Ruth A.; Abrahamson, Norman A.

    2014-01-01

    A tenet of earthquake science is that faults are locked in position until they abruptly slip during the sudden strain-relieving events that are earthquakes. Whereas it is expected that locked faults when they finally do slip will produce noticeable ground shaking, what is uncertain is how the ground shakes during earthquakes on creeping faults. Creeping faults are rare throughout much of the Earth's continental crust, but there is a group of them in the San Andreas fault system. Here we evaluate the strongest ground motions from the largest well-recorded earthquakes on creeping faults. We find that the peak ground motions generated by the creeping fault earthquakes are similar to the peak ground motions generated by earthquakes on locked faults. Our findings imply that buildings near creeping faults need to be designed to withstand the same level of shaking as those constructed near locked faults.

  3. Response of pendulums to complex input ground motion

    USGS Publications Warehouse

    Graizer, V.; Kalkan, E.

    2008-01-01

    Dynamic response of most seismological instruments and many engineering structures to ground shaking can be represented via response of a pendulum (single-degree-of-freedom oscillator). In most studies, pendulum response is simplified by considering the input from uni-axial translational motion alone. Complete ground motion however, includes not only translational components but also rotations (tilt and torsion). In this paper, complete equations of motion for three following types of pendulum are described: (i) conventional (mass-on-rod), (ii) mass-on-spring type, and (iii) inverted (astatic), then their response sensitivities to each component of complex ground motion are examined. The results of this study show that a horizontal pendulum similar to an accelerometer used in strong motion measurements is practically sensitive to translational motion and tilt only, while inverted pendulum commonly utilized to idealize multi-degree-of-freedom systems is sensitive not only to translational components, but also to angular accelerations and tilt. For better understanding of the inverted pendulum's dynamic behavior under complex ground excitation, relative contribution of each component of motion on response variants is carefully isolated. The systematically applied loading protocols indicate that vertical component of motion may create time-dependent variations on pendulum's oscillation period; yet most dramatic impact on response is produced by the tilting (rocking) component. ?? 2007 Elsevier Ltd. All rights reserved.

  4. A simple model for strong ground motions and response spectra

    USGS Publications Warehouse

    Safak, Erdal; Mueller, Charles; Boatwright, John

    1988-01-01

    A simple model for the description of strong ground motions is introduced. The model shows that response spectra can be estimated by using only four parameters of the ground motion, the RMS acceleration, effective duration and two corner frequencies that characterize the effective frequency band of the motion. The model is windowed band-limited white noise, and is developed by studying the properties of two functions, cumulative squared acceleration in the time domain, and cumulative squared amplitude spectrum in the frequency domain. Applying the methods of random vibration theory, the model leads to a simple analytical expression for the response spectra. The accuracy of the model is checked by using the ground motion recordings from the aftershock sequences of two different earthquakes and simulated accelerograms. The results show that the model gives a satisfactory estimate of the response spectra.

  5. Effects from measured ground motions at the SSC

    SciTech Connect

    Ng, King-Yuen ); Peterson, J.M. )

    1990-12-01

    The separation of the two beams in the SSC caused by ground motion produced by railroad and highway traffic crossing over the ring and by nearby quarry blasts were estimated from measured amplitude spectra using a complete optical model of the accelerator lattice, but a simplified model of the ground structure. The beam separation expected from the largest ground motion recorded from train crossings is only a few percent of the rms beam width at the beam-crossing points. However, the beam separation caused by quarry blasts are larger and can momentarily produce significant loss in luminosity. 6 refs., 15 figs., 3 tabs.

  6. Characteristics of horizontal ground motion measures along principal directions

    NASA Astrophysics Data System (ADS)

    Hong, H. P.; Goda, K.

    2010-03-01

    Ground motion records are often used to develop ground motion prediction equations (GMPEs) for a randomly oriented horizontal component, and to assess the principal directions of ground motions based on the Arias intensity tensor or the orientation of the major response axis. The former is needed for seismic hazard assessment, whereas the latter can be important for assessing structural responses under multi-directional excitations. However, a comprehensive investigation of the pseudo-spectral acceleration (PSA) and of GMPEs conditioned on different axes is currently lacking. This study investigates the principal directions of strong ground motions and their relation to the orientation of the major response axis, statistics of the PSA along the principal directions on the horizontal plane, and correlation of the PSA along the principal directions on the horizontal plane. For these, three sets of strong ground motion records, including intraplate California earthquakes, inslab Mexican earthquakes, and interface Mexican earthquakes, are used. The results indicate that one of the principal directions could be considered as quasi-vertical. By focusing on seismic excitations on the horizontal plane, the statistics of the angles between the major response axis and the major principal axis are obtained; GMPEs along the principal axes are provided and compared with those obtained for a randomly oriented horizontal component; and statistical analysis of residuals associated with GMPEs along the principal directions is carried out.

  7. Verifying a computational method for predicting extreme ground motion

    USGS Publications Warehouse

    Harris, R.A.; Barall, M.; Andrews, D.J.; Duan, B.; Ma, S.; Dunham, E.M.; Gabriel, A.-A.; Kaneko, Y.; Kase, Y.; Aagaard, B.T.; Oglesby, D.D.; Ampuero, J.-P.; Hanks, T.C.; Abrahamson, N.

    2011-01-01

    In situations where seismological data is rare or nonexistent, computer simulations may be used to predict ground motions caused by future earthquakes. This is particularly practical in the case of extreme ground motions, where engineers of special buildings may need to design for an event that has not been historically observed but which may occur in the far-distant future. Once the simulations have been performed, however, they still need to be tested. The SCEC-USGS dynamic rupture code verification exercise provides a testing mechanism for simulations that involve spontaneous earthquake rupture. We have performed this examination for the specific computer code that was used to predict maximum possible ground motion near Yucca Mountain. Our SCEC-USGS group exercises have demonstrated that the specific computer code that was used for the Yucca Mountain simulations produces similar results to those produced by other computer codes when tackling the same science problem. We also found that the 3D ground motion simulations produced smaller ground motions than the 2D simulations.

  8. Incorporating Uncertainty in Ground Motion into Damage Estimation Calculations

    NASA Astrophysics Data System (ADS)

    Latchman, S.; Simic, M.

    2012-04-01

    It is well known that a ground motion prediction equation produces not just a point estimate but a variation around this point estimate. This variation in ground motion is given by a standard deviation and ground motions can be said to be lognormally distributed. When estimating the damage to a property from an earthquake, for a given fixed ground motion intensity of say 0.5g there would be a variation in damage modelled. Therefore, there are two properties varying - the intensity of the earthquake and the vulnerability of the structure. Typically, combining the two probability distributions would be computationally expensive and possibly unrealistic if a large number of locations were being modelled. This paper seeks to investigate theoretically how the two distributions can be combined to give a single probability distribution of damage and we also investigate methods which allow this computation to be speeded up through approximations. Finally the change in mean damage amount and standard deviation after accounting for uncertainty in the ground motion (as opposed to using a point estimate) is also investigated.

  9. Development of Maximum Considered Earthquake Ground Motion Maps

    USGS Publications Warehouse

    Leyendecker, E.V.; Hunt, R.J.; Frankel, A.D.; Rukstales, K.S.

    2000-01-01

    The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. The spectral response accelerations are obtained from maps prepared following the recommendations of the Building Seismic Safety Council's (BSSC) Seismic Design Procedures Group (SDPG). The SDPG-recommended maps, the Maximum Considered Earthquake (MCE) Ground Motion Maps, are based on the U.S. Geological Survey (USGS) probabilistic hazard maps with additional modifications incorporating deterministic ground motions in selected areas and the application of engineering judgement. The MCE ground motion maps included with the 1997 NEHRP Provisions also serve as the basis for the ground motion maps used in the seismic design portions of the 2000 International Building Code and the 2000 International Residential Code. Additionally the design maps prepared for the 1997 NEHRP Provisions, combined with selected USGS probabilistic maps, are used with the 1997 NEHRP Guidelines for the Seismic Rehabilitation of Buildings.

  10. Distance and azimuthal dependence of ground-motion variability

    NASA Astrophysics Data System (ADS)

    Vyas, Jagdish Chandra; Mai, Paul Martin; Galis, Martin

    2016-04-01

    We investigate the near-field ground-motion variability by computing the seismic wavefield for five previously published kinematic rupture models of the M 7.3 1992 Landers earthquake, several simplified rupture models based on the Landers event, and a large M 7.8 scenario earthquake in Southern California. The ground motion simulations are accomplished by solving the elasto-dynamic equations of motion using a generalized finite-difference method. The simulated waveforms are calibrated against near-field strong-motion recordings for the Landers earthquake. We then analyze our simulation-based data-set of ground-motions, binned with respect to distance and azimuth to compute mean and standard deviation of peak ground velocity (PGV). We consider different 1D-velocity-density profiles for the Landers simulations, and a 3D heterogeneous Earth structure for the ShakeOut scenario, and for both cases we honor geometrical fault complexity. The ground-motion variability, σln(PGV), estimated from numerical simulations is higher in the near-field (Joyner-Boore distance RJB <20 km) compared to that associated with standard ground-motion prediction equations. We find that σln(PGV)decreases with increasing distance from the fault as a power law. The physical explanation of a large near-field σln(PGV)is the presence of strong directivity and rupture complexity. We also show that intra-event ground-motion variability is high in the rupture-propagation direction (both forward and backward directivity regions), but low in the direction perpendicular to rupture propagation for unilateral ruptures. We observe that the power-law decay of σln(PGV) is primarily controlled by slip heterogeneity. In addition, σln(PGV) as function of azimuth is sensitive to variations in both rupture speed and slip heterogeneity. We also find that the azimuthal dependence of mean, μln(PGV), can be approximated by a Cauchy-Lorentz function, which may potentially help in estimation of ground motion for

  11. Effect of site conditions on ground motion and damage

    USGS Publications Warehouse

    Borcherdt, R.; Glassmoyer, G.; Andrews, M.; Cranswick, E.

    1989-01-01

    Results of seismologic studies conducted by the U.S. reconnaissance team in conjunction with Soviet colleagues following the tragic earthquakes of December 7, 1988, suggest that site conditions may have been a major factor in contributing to increased damage levels in Leninakan. As the potential severity of these effects in Leninakan had not been previously identified, this chapter presents results intended to provide a preliminary quantification of these effects on both damage and levels of ground motion observed in Leninakan. The article describes the damage distribution geologic setting, ground motion amplification in Leninakan, including analog amplifications and spectral amplifications. Preliminary model estimates for site response are presented. It is concluded that ground motion amplification in the 0.5-2.5-second period range was a major contributing factor to increased damage in Leninakan as compared with Kirovakan. Leninakan is located on thick water saturated alluvial deposits.

  12. Three-dimensional simulations of ground motions in sedimentary basins

    USGS Publications Warehouse

    Frankel, Arthur

    1993-01-01

    This report describes work being done at the U.S. Geological Survey on 3-D simulations of earthquake ground motions in sedimentary basins. The ultimate goal of this research is to predict strong ground motions in sedimentary basins for expected large earthquakes. This report emphasizes the inadequacy of using flat-layered models for synthesizing ground motions in sedimentary basins. 2-D and 3-D simulations have demonstrated how the slope of the alluvium-bedrock interface can trap S-waves in the basins, producing prolonged surface wave trains. These large surface waves are not generated in 1-D flat layered models, which underestimate the duration and peak amplitude of shaking. We present results of 3-D simulations for the San Bernardino and Santa Clara valleys, California, for earthquakes on the San Andreas fault.

  13. Propagation of seismic ground motion in the Kanto Basin, Japan.

    PubMed

    Koketsu, K; Kikuchi, M

    2000-05-19

    The pattern of ground motion for a magnitude 5.7 earthquake near Tokyo was captured by 384 strong ground motion instruments across the Kanto sedimentary basin and its surroundings. The records allow the visualization of the propagation of long-period ground motion in the basin and show the refraction of surface waves at the basin edge. The refracted wave does not travel directly from the earthquake epicenter, but traverses the basin obliquely to the edge. The surface wave inside the basin propagates more slowly than that outside such that the wavefronts separate from each other, and the refracted wave heals the discrepancy in the speed of advance of the wavefronts inside and outside the basin. The refracted arrival is dominant near the edge of the Kanto basin. PMID:10817997

  14. Blind Prediction of Near-Fault Strong Ground Motions

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Graves, R.; Zeng, Y.; Somerville, P.

    2002-12-01

    The Mw 7.9 Alaska earthquake provides an unprecedented opportunity to analyze strong ground motion recordings obtained very close to a large magnitude crustal earthquake. Several strong motion sites are located along the route of the Alaska Pipeline which crosses roughly perpendicular to the fault rupture about 85 km east of the epicenter. The closest site is located about 3 km from the fault. Prior to the release of these data, we conducted a blind prediction experiment to estimate the ground motion waveforms at this closest recording site. Ground motions are computed using the both one realization of the stochastic composite source simulation methodology of Zeng (1994) and the deterministic simulation of Somerville et al. (1994). Both techniques utilize full waveform Greens functions calculated for plane layered velocity structures. Due to uncertainty in the distribution of slip during the event, the deterministic simulation used both uniform and heterogeneous models of the slip distribution. Predictions were made without accurate knowledge of site conditions or fault-station geometry. In all cases, the simulated motions are characterized by pulse-like motions that exhibit strong rupture directivity effects. Peak fault-normal ground velocities and displacements are about twice as large as corresponding peak fault-parallel motions. For the heterogeneous slip models, peak velocities for the two simulation methodologies are 50-95 cm/s, and peak dynamic displacements are 60-150 cm. In addition, these simulations predict static horizontal offsets of 50-170 cm, depending on the component. Plots of the simulated motions and more detailed descriptions of the parameterizations can be found at http://www.seismo.unr.edu/blind.

  15. DCShake: Measuring Variations in Earthquake Ground Motions in Washington, DC

    NASA Astrophysics Data System (ADS)

    Pratt, T. L.; Horton, J. W., Jr.; Hough, S. E.; Munoz, J.; Chapman, M. C.; Olgun, G.; Beale, J.

    2015-12-01

    During the 2011 Mw5.8 Mineral, VA earthquake, many buildings in Washington DC, including national landmarks like the Washington National Cathedral, the Smithsonian "Castle," and the Washington Monument, sustained damage despite being 130 km from the epicenter. The surprisingly large amount of damage from weak bedrock ground motions raises questions of whether and how the local geologic materials beneath the city amplify ground motions. In particular, how much and at what frequencies do the southeast-thickening sedimentary strata of the Atlantic Coastal Plain (ACP) strata, sitting on crystalline bedrock, amplify and possibly trap energy? Between November 2014 and August 2015, we used 27 seismometers to measure ground motions across the city during teleseismic and regional earthquakes. Four sites on Piedmont crystalline rocks in NW Washington served as bedrock reference sites, and 23 sites were on ACP strata between 11 m and 200 m thick. Recordings of teleseisms and regional earthquakes provide data with sufficiently high signal-to-noise for computing spectral ratios of the horizontal ground shaking relative to the average of the 4 bedrock sites. Preliminary results are consistent with the primary influence on the amplitudes of ground motions coming from the ACP strata. At frequencies below 1 Hz most sites showed little difference in amplification relative to bedrock, suggesting that basement rocks beneath the ACP strata exert little influence on ground shaking. Strong spectral amplifications of a factor or 10 or greater at frequencies of 1 Hz and above are interpreted as being caused by the ACP strata, with the largest amplitudes at frequencies near the fundamental resonance frequency. A gradual decrease in amplification with higher frequencies above the fundamental peak is consistent with harmonics and resonances from within ACP strata. Results indicate significant amplification of ground motions in the DC area, the frequencies of which will be compared to the

  16. Strong Ground Motion Estimation During the Kutch, India Earthquake

    NASA Astrophysics Data System (ADS)

    Iyengar, R. N.; Kanth, S. T. G. Raghu

    2006-01-01

    In the absence of strong motion records, ground motion during the 26th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g 0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.

  17. Ground motion hazard from supershear rupture

    USGS Publications Warehouse

    Andrews, D.J.

    2010-01-01

    An idealized rupture, propagating smoothly near a terminal rupture velocity, radiates energy that is focused into a beam. For rupture velocity less than the S-wave speed, radiated energy is concentrated in a beam of intense fault-normal velocity near the projection of the rupture trace. Although confined to a narrow range of azimuths, this beam diverges and attenuates. For rupture velocity greater than the S-wave speed, radiated energy is concentrated in Mach waves forming a pair of beams propagating obliquely away from the fault. These beams do not attenuate until diffraction becomes effective at large distance. Events with supershear and sub-Rayleigh rupture velocity are compared in 2D plane-strain calculations with equal stress drop, fracture energy, and rupture length; only static friction is changed to determine the rupture velocity. Peak velocity in the sub-Rayleigh case near the termination of rupture is larger than peak velocity in the Mach wave in the supershear case. The occurrence of supershear rupture propagation reduces the most intense peak ground velocity near the fault, but it increases peak velocity within a beam at greater distances. ?? 2010.

  18. Recovery of Near-Fault Ground Motion by Introducing Rotational Motions

    NASA Astrophysics Data System (ADS)

    Chiu, H. C.

    2014-12-01

    Near-fault ground motion is the key data to seismologists for revealing the seismic faulting and earthquake physics and strong-motion data is the only near-fault seismogram that can keep on-scale recording in a major earthquake. Unfortunately, this type of data might be contaminated by the rotation induced effects such as the centrifugal acceleration and the gravity effects. We analyze these effects based on a set of collocated rotation-translation data of small to moderate earthquakes. Results show these rotation effects could be negligible in small ground motion, but they might have a radical growing in the near-fault/extremely large ground motions. In order to extract more information from near-fault seismogram for improving our understating of seismic faulting and earthquake physics, it requires six-component collocated rotation-translation records to reduce or remove these effects.

  19. Ground motion measurements from the demolition of steel towers

    SciTech Connect

    Joshi, J.R.; Lee, R.C.

    1998-12-31

    Steel towers from a decommissioned heavy water plant were to be demolished. Ground motions due to the proposed felling were estimated in order to assess the structural integrity of neighboring buildings and piping systems. The extraction towers were 125 feet (38.1 m) high in two sizes: 6.5 and 11 feet (1.98 and 3.35 m) inside diameters weighing 215 X 10{sup 3} and 470 X 10{sup 3} lb (956 X 10{sup 3} and 2.1 X 10{sup 6} N). The total potential energy of the tower collapse was about 15 X 10{sup 6} and 32 X 10{sup 6} ft-lb (20.3 X 10{sup 6} and 43.4 X 10{sup 6} Nm) for the small and large towers, respectively. The ground motion predictions were based on a credible theoretical relationship with constants estimated from data available for a different location at the site for dynamic compaction with an energy input an order of magnitude less than that for the towers. Due to the uncertainty of prediction of ground motions a coefficient of variation of 2.0 was used in the structural assessment. Ground motion from the collapse of the extraction towers were monitored by several 3- and 6-components seismographs. Recorded measurements indicated that the ground motion was less than the predicted values. Peak radial motions were approximately equal to the vertical ones. Video tapes of the demolition suggested significant internal energy losses. The measurements suggested that the tower potential energy conversion to dynamic impact energy was about 25 percent. 7 figs.

  20. Ground motion modeling of Hayward fault scenario earthquakes II:Simulation of long-period and broadband ground motions

    SciTech Connect

    Aagaard, B T; Graves, R W; Rodgers, A; Brocher, T M; Simpson, R W; Dreger, D; Petersson, N A; Larsen, S C; Ma, S; Jachens, R C

    2009-11-04

    We simulate long-period (T > 1.0-2.0 s) and broadband (T > 0.1 s) ground motions for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.

  1. Ground-motion modeling of Hayward fault scenario earthquakes, part II: Simulation of long-period and broadband ground motions

    USGS Publications Warehouse

    Aagaard, Brad T.; Graves, Robert W.; Rodgers, Arthur; Brocher, Thomas M.; Simpson, Robert W.; Dreger, Douglas; Petersson, N. Anders; Larsen, Shawn C.; Ma, Shuo; Jachens, Robert C.

    2010-01-01

    We simulate long-period (T>1.0–2.0 s) and broadband (T>0.1 s) ground motions for 39 scenario earthquakes (Mw 6.7–7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault, we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions, compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area, with about 50% of the urban area experiencing modified Mercalli intensity VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland earthquake and the 2007 Mw 5.45 Alum Rock earthquake show that the U.S. Geological Survey’s Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area for Hayward fault earthquakes, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions for the suite of scenarios exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute much of this difference to the seismic velocity structure in the San Francisco Bay area and how the NGA models account for basin amplification; the NGA relations may underpredict amplification in shallow sedimentary basins. The simulations also suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by increasing the areal extent of rupture directivity with period.

  2. Description of ground motion data processing codes, volume 2

    NASA Astrophysics Data System (ADS)

    Sanders, M. L.

    1988-02-01

    Data processing codes developed to process ground motion at the Nevada Test Site for the Weapons Test Seismic Investigations Project are used today as part of the program to process ground motion records for the Nevada Nuclear Waste Investigations Project. The work contained in this report documents and lists these codes and verifies the PSRV code. Volume 1, which contains the program specifications for the scientific and engineering software, consists of the following programs: SPECTRA calculates the power density spectrum of digitized time histories from underground nuclear explosions (UNEs); FILTER designs optimum finite impulse response filters and then filters UNE ground motion data; and PSRV calculates the pseudo-relative velocity response spectrum for UNE ground motions. Volume 2 contains the following program specifications for the auxiliary software. ACCESS allows the user to scan, update, delete, or add records contained in the Weapons Test Seismic Investigations data base. SCAN produces an inventory of the time histories contained in a large data file. PLOT plots the data files: ROTATE converts data in the horizontal plane into a UNE specific coordinate system; and VECTOR calculates the magnitude versus time of the 2-D (horizontal components) and 3-D (vertical and horizontal components) vectors. Volume 3 comprises the users' manuals for each of the programs described in Volumes 1 and 2.

  3. VLHC/NLC slow ground motion studies in Illinois

    SciTech Connect

    Vladimir Shiltsev et al.

    2001-07-02

    Since October 1999 we carry out continuous measurements of the slow ground motion on and nearby Fermilab site with a primary goal to provide experimental data for the Very Large Hadron Collider (VLHC) and Next Linear Collider (NLC) projects. Here we give a general description of the experimental set-up, present main results and discuss consequences for the colliders.

  4. Modal-pushover-based ground-motion scaling procedure

    USGS Publications Warehouse

    Kalkan, Erol; Chopra, Anil K.

    2011-01-01

    Earthquake engineering is increasingly using nonlinear response history analysis (RHA) to demonstrate the performance of structures. This rigorous method of analysis requires selection and scaling of ground motions appropriate to design hazard levels. This paper presents a modal-pushover-based scaling (MPS) procedure to scale ground motions for use in a nonlinear RHA of buildings. In the MPS method, the ground motions are scaled to match to a specified tolerance, a target value of the inelastic deformation of the first-mode inelastic single-degree-of-freedom (SDF) system whose properties are determined by the first-mode pushover analysis. Appropriate for first-mode dominated structures, this approach is extended for structures with significant contributions of higher modes by considering elastic deformation of second-mode SDF systems in selecting a subset of the scaled ground motions. Based on results presented for three actual buildings-4, 6, and 13-story-the accuracy and efficiency of the MPS procedure are established and its superiority over the ASCE/SEI 7-05 scaling procedure is demonstrated.

  5. Developments in Ground-Motion Modeling in Eastern North America

    NASA Astrophysics Data System (ADS)

    Atkinson, G. M.; Boore, D. M.

    2012-12-01

    Recent well-recorded earthquakes in Eastern North America (ENA) have led us to re-evaluate concepts that have been "standard fare" in the development of ground-motion prediction equations (GMPEs) for ENA for decades, including all published GMPEs that are used in current practice (e.g. Atkinson and Boore, 2011, 2006, 1995; Pezeshk et al., 2011; Campbell, 2003; Toro et al., 1997, etc.). Assumptions common to all ENA GMPEs that may not be true include the following. (1) Typical ENA stress drops, in the context of a Brune model representation of the source spectrum, are in the range of 150-300 bars, with the exception of occasional high-stress events like the 1988 Saguenay earthquake. (2) Attenuation of ground motions can be modeled with a frequency-independent geometric spreading function, either bilinear or trilinear in shape (e.g. Street and Turcotte, 1975; Herrmann and Kijko, 1983; Atkinson and Mereu, 1992; Atkinson, 2004; Boatwright and Seekins, 2011), and an associated frequency-dependent anelastic attenuation term related to the regional Quality factor. The use of a bilinear or trilinear form models the transition from geometric spreading of body waves at close distances to slower surface-wave-type spreading at regional distances. We use ground-motion recordings from recent ENA events to re-examine these basic tenets of GMPE development, in light of constraints on the problem provided at low frequencies by seismic moment, and at high frequencies by stresses inferred from Empirical Greens Function (EGF) analysis. We find strong evidence, in both ground-motion data and from the constraints, that geometric attenuation may be frequency dependent. Moreover, EGF stress drops may be very high (>500 bars) - but they do not lead to particularly large high-frequency ground motions, at least at distances for which we have observations. More complex models of ENA source and attenuation processes appear to be required in order to reconcile our growing ground-motion database

  6. Japan Meteorological Agency information on long-period ground motion

    NASA Astrophysics Data System (ADS)

    Aizawa, K.; Kawazoe, Y.; Uratani, J.; Sakihara, H.; Nakamura, M.

    2013-12-01

    An earthquake generates seismic waves with various periods, and earthquakes with larger magnitudes generate stronger long-period ground motions. When the natural period of a high-rise building is close to the predominant period of ground motion, resonance happens and the building is severely shaken longer than surface of the Earth. Today, more and more people spend time in high-rise buildings especially in metropolitan areas. If great earthquake occurs, many people in high-rise buildings will be affected by long-period ground motion. During the 2011 Great East Japan Earthquake, high-rise buildings in Osaka City which locates more than 700 km away from the epicenter were shaken severely at higher floors by the long-period ground motion. In a building, maximum acceleration was 34cm/s/s at the ground level, and 130 cm/s/s at the 52nd floors in the same building. Fortunately there was no structural damage in the building, but non-structural elements at higher floors suffered damage: fall of ceiling boards, deformation of partition walls. As near-ground floors of the building were not very shaken severely, building managers on the floors could not be aware of higher floors' disastrous situation. To notify people of such situations and facilitate effective countermeasures, Japan Meteorological Agency(JMA) started to provide information on long-period ground motion from March 28th, 2013. Based on questionnaires to tenants of high-rise buildings, it has become clear that difficulty of people's activities depends on the velocity of floor movement, and we classified the intensity of long-period ground motion into four on the basis of velocity. To get the classification, we use wave forms observed by JMA seismic intensity meters on the surface of the Earth which are automatically sent to the JMA system. To estimate shaking at higher floors from wave forms on the surface of the Earth, we simulate the shaking of buildings by absolute velocity response spectrum of the period

  7. Soil response to earthquake ground motion: Final report

    SciTech Connect

    Silva, W.

    1988-03-01

    The validity of two fundamental assumptions in the analysis of dynamic site response to earthquake ground motion is examined: (1) The adequacy of modeling at a site by vertically propagation shear waves was evaluated using data recorded by vertical arrays. Results suggest that about 75% of the power observed at the surface of a soft site can be modeled as vertically propagating shear waves, and only in a limited bandwidth from several seconds to 15 Hz. The remaining 25% of the total surface power may arise from scattered or laterally propagating seismic energy. The implications of this on deconvolution of ground motion to depth is discussed. (2) The strain dependence of in-situ material properties was examined using strong and weak ground motion recorded at soil sites and at nearby rock sites. Response and Fourier spectra obtained from site response analyses using linear, equivalent-linear, and nonlinear (STEALTH) techniques were compared to each other and to observed data. The results suggest nonlinear soil response occurred only for surface motion in excess of 30% g. The transition region from linear to nonlinear response may be abrupt and occurred at strain levels around 10/sup -2/%. 114 refs., 93 figs., 6 tabs

  8. Ground Motion Relations While TBM Drilling in Unconsolidated Sediments

    NASA Astrophysics Data System (ADS)

    Grund, Michael; Ritter, Joachim R. R.; Gehrig, Manuel

    2016-05-01

    The induced ground motions due to the tunnel boring machine (TBM), which has been used for the drilling of the urban metro tunnel in Karlsruhe (SW Germany), has been studied using the continuous recordings of seven seismological monitoring stations. The drilling has been undertaken in unconsolidated sediments of the Rhine River system, relatively close to the surface at 6-20 m depth and in the vicinity of many historic buildings. Compared to the reference values of DIN 4150-3 (1-80 Hz), no exceedance of the recommended peak ground velocity (PGV) limits (3-5 mm/s) was observed at the single recording site locations on building basements during the observation period between October 2014 and February 2015. Detailed analyses in the time and frequency domains helped with the detection of the sources of several specific shaking signals in the recorded time series and with the comparison of the aforementioned TBM-induced signals. The amplitude analysis allowed for the determination of a PGV attenuation relation (quality factor Q ~ 30-50) and the comparison of the TBM-induced ground motion with other artificially induced and natural ground motions of similar amplitudes.

  9. Statistical study of ground motion amplification in the Mississippi embayment

    NASA Astrophysics Data System (ADS)

    Malekmohammadi, Mojtaba

    Three important topics have been studied in this dissertation. First, the effects of deep soil deposits of the Mississippi embayment in ground motion amplification have been studied. Using the results of one-dimensional analyses, a parametric model is developed for the region to estimate the ground motion amplification. The averaged shear-wave velocity in the upper 30 meter, Vs30, ranging from 220 to 800 m/s and deposit thickness varying from 70 to 750m, are considered in the estimation of the ground motion amplification with respect to a generic bedrock profile of the Mississippi embayment. Results indicate that site factors suggested by seismic codes cannot capture the site properties of the Mississippi embayment and are not appropriate for the region. In the second part, a new step-by-step method is developed to select a set of ground motions which takes into account a site-specific Probabilistic Seismic Hazard Analysis (PSHA) and the associated uncertainties through the defined logic tree. In the proposed method, after capturing the variability of the Uniform Hazard Response Spectrum (UHRS), I used a Monte Carlo procedure to produce a set of response spectra that has mean equals to the target and variability close to the variability of the target at all the spectral periods. Each member of the generated set is called individual target response spectra, and ground motions from the database of real data and also synthetic ground motions are selected based on their similarity with the individual target response spectra. The method's procedure is defined through studying a sample site in North of the Mississippi embayment. In the last part of the study I developed a model for the ratio of Vertical to Horizontal component of earthquakes (V/H ratio) for the Mississippi embayment. This model can be used in developing the site-specific vertical design spectrum for the region by scaling the horizontal design spectrum resulting from a PSHA. The input parameters of the

  10. Evaluation of Ground-Motion Modeling Techniques for Use in Global ShakeMap - A Critique of Instrumental Ground-Motion Prediction Equations, Peak Ground Motion to Macroseismic Intensity Conversions, and Macroseismic Intensity Predictions in Different Tectonic Settings

    USGS Publications Warehouse

    Allen, Trevor I.; Wald, David J.

    2009-01-01

    Regional differences in ground-motion attenuation have long been thought to add uncertainty in the prediction of ground motion. However, a growing body of evidence suggests that regional differences in ground-motion attenuation may not be as significant as previously thought and that the key differences between regions may be a consequence of limitations in ground-motion datasets over incomplete magnitude and distance ranges. Undoubtedly, regional differences in attenuation can exist owing to differences in crustal structure and tectonic setting, and these can contribute to differences in ground-motion attenuation at larger source-receiver distances. Herein, we examine the use of a variety of techniques for the prediction of several ground-motion metrics (peak ground acceleration and velocity, response spectral ordinates, and macroseismic intensity) and compare them against a global dataset of instrumental ground-motion recordings and intensity assignments. The primary goal of this study is to determine whether existing ground-motion prediction techniques are applicable for use in the U.S. Geological Survey's Global ShakeMap and Prompt Assessment of Global Earthquakes for Response (PAGER). We seek the most appropriate ground-motion predictive technique, or techniques, for each of the tectonic regimes considered: shallow active crust, subduction zone, and stable continental region.

  11. Ground Motion Prediction Trends For Eastern North America Based on the Next Generation Attenuation East Ground Motion Database

    NASA Astrophysics Data System (ADS)

    Cramer, C. H.; Kutliroff, J.; Dangkua, D.

    2010-12-01

    A five-year Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), has begun at the Pacific Earthquake Engineering Research (PEER) Center funded by the Nuclear Regulatory Commission (NRC), the U.S. Geological Survey (USGS), the Electric Power Research Institute (EPRI), and the Department of Energy (DOE). The initial effort focused on database design and collection of appropriate M>4 ENA broadband and accelerograph records to populate the database. Ongoing work has focused on adding records from smaller ENA earthquakes and from other SCRs such as Europe, Australia, and India. Currently, over 6500 horizontal and vertical component records from 60 ENA earthquakes have been collected and prepared (instrument response removed, filtering to acceptable-signal band, determining peak and spectral parameter values, quality assurance, etc.) for the database. Geologic Survey of Canada (GSC) strong motion recordings, previously not available, have also been added to the NGA East database. The additional earthquakes increase the number of ground motion recordings in the 10 - 100 km range, particularly from the 2008 M5.2 Mt. Carmel, IL event, and the 2005 M4.7 Riviere du Loup and 2010 M5.0 Val des Bois earthquakes in Quebec, Canada. The goal is to complete the ENA database and make it available in 2011 followed by a SCR database in 2012. Comparisons of ground motion observations from four recent M5 ENA earthquakes with current ENA ground motion prediction equations (GMPEs) suggest that current GMPEs, as a group, reasonably agree with M5 observations at short periods, particularly at distances less than 200 km. However, at one second, current GMPEs over predict M5 ground motion observations. The 2001 M7.6 Bhuj, India, earthquake provides some constraint at large magnitudes, as geology and regional attenuation is analogous to ENA. Cramer and Kumar, 2003, have

  12. Nonlinear Strong Ground Motion in the 2004 Parkfield Earthquake

    NASA Astrophysics Data System (ADS)

    Rubinstein, J. L.; Beroza, G. C.

    2004-12-01

    Previous studies [Rubinstein and Beroza, 2004 (a,b); Schaff and Beroza, 2004] have shown that the strong shaking resultant from medium and large earthquakes can result in the formation and/or growth of microcracks in the near surface, resulting in reduced seismic velocities at distances exceeding 30km. We use moving window cross correlation on the waveforms of repeating earthquake sequences in the Parkfield area to identify temporal changes in wave propagation coincident with the earthquake, evidence of the damage that the Parkfield earthquake caused. The largest delays we observe are in the S coda, and exceed 10ms. Parkfield provides a unique opportunity where we can better understand to what depth damage caused by strong ground motion (nonlinear strong ground motion) occurs as there are many downhole and uphole seismometers in the region.

  13. Tectonic stability and expected ground motion at Yucca Mountain

    SciTech Connect

    1984-10-02

    A workshop was convened on August 7-8, 1984 at the direction of DOE to discuss effects of natural and artificial earthquakes and associated ground motion as related to siting of a high-level radioactive waste (HLW) repository at Yucca Mountain, Nevada. A panel of experts in seismology and tectonics was assembled to review available data and analyses and to assess conflicting opinions on geological and seismologic data. The objective of the meeting was to advise the Nevada Nuclear Waste Storage Investigations (NNWSI) Project about how to present a technically balanced and scientifically credible evaluation of Yucca Mountain for the NNWSI Project EA. The group considered two central issues: the magnitude of ground motion at Yucca Mountain due to the largest expected earthquake, and the overall tectonic stability of the site given the current geologic and seismologic data base. 44 refs.

  14. Directivity in NGA earthquake ground motions: Analysis using isochrone theory

    USGS Publications Warehouse

    Spudich, P.; Chiou, B.S.J.

    2008-01-01

    We present correction factors that may be applied to the ground motion prediction relations of Abrahamson and Silva, Boore and Atkinson, Campbell and Bozorgnia, and Chiou and Youngs (all in this volume) to model the azimuthally varying distribution of the GMRotI50 component of ground motion (commonly called 'directivity') around earthquakes. Our correction factors may be used for planar or nonplanar faults having any dip or slip rake (faulting mechanism). Our correction factors predict directivity-induced variations of spectral acceleration that are roughly half of the strike-slip variations predicted by Somerville et al. (1997), and use of our factors reduces record-to-record sigma by about 2-20% at 5 sec or greater period. ?? 2008, Earthquake Engineering Research Institute.

  15. Modeling Long-Period Ground Motions for Marmara Region

    NASA Astrophysics Data System (ADS)

    Demircioglu, M.; Sesetyan, K.; Erdik, M.; Durukal, E.

    2007-12-01

    As a consequence of the change of paradigm in earthquake resistant design stronger design earthquakes now control the seismic design of important structures. These stronger earthquakes include the effects of near-field pulses, fault-normal motions, and near-field deep soil site motions. As a consequence, there is a strong need for the development of robust and reliable techniques for the assessment of long period earthquake ground motions especially for near field conditions. To provide an example to the assessment of long period ground motion a comparative study has been carried out for the Marmara Region, Turkey. The probabilistic earthquake hazard has been investigated using PEER-NGA (2007) and older generation attenuation relationships for PGA and SA (0.2s, 1s, 2s, 4s, 6s, 8s and 10s) corresponding to 50, 10 and 2 percent probabilities of exceedance in 50 years. PGA values were used to obtain the EuroCode whereas, SA(0.2s and 1s) were used to obtain the NEHRP (2003) based response spectra. SA (0.2s, 1s, 2s, 4s, 6s, 8s and 10s) values were used to plot the equi-hazard spectrum. Furthermore associated hazard deaggregation has been conducted for several selected sites to obtain rational estimates of the deterministic long period spectral accelerations and the deterministic spectral shapes. Comparison of the findings indicate significant variation of long period spectral accelerations. The accuracy of seismic design spectra given in current codes is not sufficient at these periods. There is also a need to develop guidelines for the selection of design basis ground motion for long period or highly nonlinear (softening) structure.

  16. Ground Motion Saturation Evaluation (GMSE) Data Needs Workshop

    SciTech Connect

    NA

    2004-07-13

    The objective of the data needs workshop is to identify potential near-term (12-18 month) studies that would reduce uncertainty in extremely low probability (< 10{sup -5}/yr) earthquake ground motions at Yucca Mountain. Recommendations made at the workshop will be considered by BSC and DOE management in formulating plans for FY05 seismic-related investigations. Based on studies done earlier this year, a bound on peak ground velocities (PGVs), consisting of a uniform distribution from 150 cm/s to 500 cm/s, has been applied to the existing PGV hazard curve for the underground repository horizon, for use in the forthcoming License Application. The technical basis for this bounding distribution is being documented, along with the basis for a slightly less conservative bound in the form of a roughly triangular distribution from 153 cm/s to 451 cm/s. The objective of the GMSE studies is to provide a technical basis for reducing remaining excessive conservatism, if any, in the extremely low probability ground motions that are used in postclosure performance assessments. Potential studies that have already been suggested include: (1) Additional tests of failure-strains of repository rocks, at, above, and below the repository horizon; (2) Identification and evaluation of nuclear explosion data that may help establish strain limits in tuff; (3) Numerical modeling of seismic wave propagation through repository rock column to test hypothesis that nonwelded tuffs below the repository horizon would fail in tension and prevent extreme strains from being transmitted to the repository; (4) Evaluation of seismic failure threshold of bladed, fragile-appearing lithophysal crystals; (5) Evaluation of whether a ground motion parameter other than PGV would correlate better with calculated drip-shield and waste-package damage states; (6) Qualification and use of finite seismic-source model to evaluate probabilities of extreme ground motions from extreme scenario earthquakes (e

  17. Earthquake ground-motion prediction equations for eastern North America

    USGS Publications Warehouse

    Atkinson, G.M.; Boore, D.M.

    2006-01-01

    New earthquake ground-motion relations for hard-rock and soil sites in eastern North America (ENA), including estimates of their aleatory uncertainty (variability) have been developed based on a stochastic finite-fault model. The model incorporates new information obtained from ENA seismographic data gathered over the past 10 years, including three-component broadband data that provide new information on ENA source and path effects. Our new prediction equations are similar to the previous ground-motion prediction equations of Atkinson and Boore (1995), which were based on a stochastic point-source model. The main difference is that high-frequency amplitudes (f ??? 5 Hz) are less than previously predicted (by about a factor of 1.6 within 100 km), because of a slightly lower average stress parameter (140 bars versus 180 bars) and a steeper near-source attenuation. At frequencies less than 5 Hz, the predicted ground motions from the new equations are generally within 25% of those predicted by Atkinson and Boore (1995). The prediction equations agree well with available ENA ground-motion data as evidenced by near-zero average residuals (within a factor of 1.2) for all frequencies, and the lack of any significant residual trends with distance. However, there is a tendency to positive residuals for moderate events at high frequencies in the distance range from 30 to 100 km (by as much as a factor of 2). This indicates epistemic uncertainty in the prediction model. The positive residuals for moderate events at < 100 km could be eliminated by an increased stress parameter, at the cost of producing negative residuals in other magnitude-distance ranges; adjustment factors to the equations are provided that may be used to model this effect.

  18. Measurements of ground motion and magnet vibrations at the APS

    SciTech Connect

    Shiltsev, V.

    1996-09-01

    This article presents results of ground motion and magnet vibrations measurements at the Advanced Photon Source. The experiments were done over a wide, frequency range (0-05-100 Hz) with the use of SM-3KV-type seismic probes from the Budker Institute of Nuclear Physics (Russia). Spectral power densities of vertical and horizontal motions of the APS hall floor and quadrupoles on regular supports were obtained. Also investigated were magnet vibrations induced by designed cooling water flow and spectral characteristics of spatial correlation of the quadrupole vibrations at different sectors of the ring. The influence of personnel activity in the hall and traffic under the ring on the slow motion of storage ring elements were observed. Amplitudes of vibrations at the APS are compared with results of seismic measurements at some other accelerators.

  19. Guidelines for ground motion definition for the eastern United States

    SciTech Connect

    Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

    1985-06-01

    Guidelines for the determination of earthquake ground motion definition for the eastern United States are established here. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large- to great-sized earthquakes (M/sub s/ > 7.5) have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes has been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data have been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data, a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the safe shutdown earthquake (SSE). A new procedure for establishing the operating basis earthquake (OBE) is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., figs., tabs.

  20. Subterranean ground motion studies for the Einstein Telescope

    NASA Astrophysics Data System (ADS)

    Beker, M. G.; van den Brand, J. F. J.; Rabeling, D. S.

    2015-01-01

    Seismic motion limits the low-frequency sensitivity of ground-based gravitational wave detectors. A conceptual design study into the feasibility of a future-generation gravitational wave observatory, coined the Einstein Telescope, has been completed. As part of this design phase, we performed a ground motion study to determine the seismic noise characteristics at various sites across the globe. This investigation focused on underground sites and encompassed a variety of geologies, including clay, salt, and hard rock, at 15 locations in nine European countries, the USA, and Japan. In addition, we analyzed data from the Virtual European Broadband Seismograph Network to characterize European seismic motion. We show that, in the region of interest for future-generation gravitational wave detectors (1-10 Hz), seismic motion is dominated by activity from anthropogenic sources. A number of sites were found that exhibited a reduction in seismic power of several orders of magnitude with respect to current detector sites, thus making it possible to set requirements for the Einstein Telescope seismic noise environment.

  1. Terrafirma: A Pan-European Ground Motion Hazard Information Service

    NASA Astrophysics Data System (ADS)

    Cooksley, Geraint

    2010-12-01

    Supported by the European Space Agency's GMES programme, Terrafirma Stage 3 (TF3) is the continuation of the Terrafirma project, a pan-European ground motion hazard information service. This third stage of the project was launched in December of 2009 and has as its aim the sustainability of the terrain motion service. TF3 features a new focus on several thematic lines for terrain motion analysis: - Tectonics - Flooding - Hydrogeology (ground water issues, landslides & inactive mines) As in previous stages, TF3 services are based on advanced satellite interferometry products (in the main using Persistent Scatterer InSAR methodologies), however they exploit additional data sources, including non-EO, coupled with expert interpretation specific to each thematic line. In addition to the three thematic lines, a wide area terrain motion mapping service will be developed and tested. The project consortium is lead by Altamira Information, with the Dutch Geological Survey (TNO) leading the Flood Theme, the Italian National Institute of Geophysics and Volcanology (INGV) leading the Tectonics Theme, and the University of Florence (UNIFI) leading the Hydrogeology Theme. The Wide Area Mapping task is lead by the German Space Agency (DLR). Its services are delivered to civil protection agencies, disaster management organisms, and coastal, rail and motorway authorities to support the process of risk assessment and mitigation. An overview of the Terrafirma project and the main highlights of the third stage are given.

  2. New Ground Motion Prediction Models for Caucasus Region

    NASA Astrophysics Data System (ADS)

    Jorjiashvili, N.

    2012-12-01

    The Caucasus is a region of numerous natural hazards and ensuing disasters. Analysis of the losses due to past disasters indicates the those most catastrophic in the region have historically been due to strong earthquakes. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration because this parameter gives useful information for Seismic Hazard Assessment. Because of this, many peak ground acceleration attenuation relations have been developed by different authors. Besides, a few attenuation relations were developed for Caucasus region: Ambraseys et al. (1996,2005) which were based on entire European region and they were not focused locally on Caucasus Region; Smit et.al. (2000) that was based on a small amount of acceleration data that really is not enough. Since 2003 construction of Georgian Digital Seismic Network has started with the help of number of International organizations, Projects and Private companies. The works conducted involved scientific as well as organizational activities: Resolving technical problems concerning communication and data transmission. Thus, today we have a possibility to get real time data and make scientific research based on digital seismic data. Generally, ground motion and damage are influenced by the magnitude of the earthquake, the distance from the seismic source to site, the local ground conditions and the characteristics of buildings. Estimation of expected ground motion is a fundamental earthquake hazard assessment. This is the reason why this topic is emphasized in this study. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models are obtained by classical, statistical way, regression analysis. Also site ground conditions are considered because the same earthquake recorded at the same distance may cause different damage

  3. Seismic Data for Evaluation of Ground Motion Hazards in Las Vegas in Support of Test Site Readiness Ground Motion

    SciTech Connect

    Rodgers, A

    2008-01-16

    In this report we describe the data sets used to evaluate ground motion hazards in Las Vegas from nuclear tests at the Nevada Test Site. This analysis is presented in Rodgers et al. (2005, 2006) and includes 13 nuclear explosions recorded at the John Blume and Associates network, the Little Skull Mountain earthquake and a temporary deployment of broadband station in Las Vegas. The data are available in SAC format on CD-ROM as an appendix to this report.

  4. Ground motion modeling of the 1906 San Francisco earthquake II: Ground motion estimates for the 1906 earthquake and scenario events

    SciTech Connect

    Aagaard, B; Brocher, T; Dreger, D; Frankel, A; Graves, R; Harmsen, S; Hartzell, S; Larsen, S; McCandless, K; Nilsson, S; Petersson, N A; Rodgers, A; Sjogreen, B; Tkalcic, H; Zoback, M L

    2007-02-09

    We estimate the ground motions produced by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

  5. Ground-Motion Simulation in the Lower Tagus Valley Basin

    NASA Astrophysics Data System (ADS)

    Borges, J. F.; Bezzeghoud, M.; Caldeira, B.; Carvalho, João

    2015-09-01

    Throughout history, the Lower Tagus Valley (LTV) region has been shaken by several earthquakes, including some with moderate to large magnitudes and with sources located inside the basin, for example the 1344 (M6.0) and 1909 (M6.0) earthquakes. Previous simulations (B ezzeghoud et al. Natural Hazard 69: 1229-1245, 2011) have revealed strong amplification of the amplitude waves in the region, because of the effect of the low-velocity sediments that fill the basin. The model used in those simulations was updated in this work by including new high-resolution geophysical and geotechnical data available for the area (seismic reflection, aeromagnetic, gravimetric, deep wells, standard penetration tests, and geological data). To contribute to improved assessment of seismic hazard in the LTV, we simulated propagation of seismic waves produced by moderate earthquakes in a 3D heterogeneous medium by using elastic finite-difference wave propagation code. The method, successfully used by G randin et al. (Geophys J Int 171: 1144-1161, 2007), involves evaluation of the seismic potential of known faults in the area studied and three-dimensional seismic ground motion modelling by use of finite difference methods. On the basis of this methodology, we calculated the ground motion for the April 23, 1909, Benavente (Portugal) earthquake ( Mw = 6.0) in dense grid points, then computed the synthetic isoseismic map of the area by use of appropriate relationships between seismic intensity (MMI) and peak ground velocity (PGV). The synthetic results, in contrast with available macroseismic and instrumental data, enable validation of the source models proposed for the area, identification of the sources of historical earthquakes, and could also indicate which areas are more exposed to seismic ground motion.

  6. Strong Ground Motion Database System for the Mexican Seismic Network

    NASA Astrophysics Data System (ADS)

    Perez-Yanez, C.; Ramirez-Guzman, L.; Ruiz, A. L.; Delgado, R.; Macías, M. A.; Sandoval, H.; Alcántara, L.; Quiroz, A.

    2014-12-01

    A web-based system for strong Mexican ground motion records dissemination and archival is presented. More than 50 years of continuous strong ground motion instrumentation and monitoring in Mexico have provided a fundamental resource -several thousands of accelerograms- for better understanding earthquakes and their effects in the region. Lead by the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM), the engineering strong ground motion monitoring program at IE relies on a continuously growing network, that at present includes more than 100 free-field stations and provides coverage to the seismic zones in the country. Among the stations, approximately 25% send the observed acceleration to a processing center in Mexico City in real-time, and the rest require manual access, remote or in situ, for later processing and cataloguing. As part of a collaboration agreement between UNAM and the National Center for Disaster Prevention, regarding the construction and operation of a unified seismic network, a web system was developed to allow access to UNAM's engineering strong motion archive and host data from other institutions. The system allows data searches under a relational database schema, following a general structure relying on four databases containing the: 1) free-field stations, 2) epicentral location associated with the strong motion records available, 3) strong motion catalogue, and 4) acceleration files -the core of the system. In order to locate and easily access one or several records of the data bank, the web system presents a variety of parameters that can be involved in a query (seismic event, region boundary, station name or ID, radial distance to source or peak acceleration). This homogeneous platform has been designed to facilitate dissemination and processing of the information worldwide. Each file, in a standard format, contains information regarding the recording instrument, the station, the corresponding earthquake

  7. Seismic design technology for breeder reactor structures. Volume 1. Special topics in earthquake ground motion

    SciTech Connect

    Reddy, D.P.

    1983-04-01

    This report is divided into twelve chapters: seismic hazard analysis procedures, statistical and probabilistic considerations, vertical ground motion characteristics, vertical ground response spectrum shapes, effects of inclined rock strata on site response, correlation of ground response spectra with intensity, intensity attenuation relationships, peak ground acceleration in the very mean field, statistical analysis of response spectral amplitudes, contributions of body and surface waves, evaluation of ground motion characteristics, and design earthquake motions. (DLC)

  8. Mitigating ground-based sensor failures with video motion detection

    NASA Astrophysics Data System (ADS)

    Macior, Robert E.; Knauth, Jonathan P.; Walter, Sharon M.; Evans, Richard

    2008-10-01

    Unattended Ground Sensor (UGS) systems typically employ distributed sensor nodes utilizing seismic, magnetic or passive IR sensing modalities to alarm if activity is present. The use of an imaging component to verify sensor events is beneficial to create actionable intelligence. Integration of the ground-based images with other ISR data requires that the images contain valid activity and are appropriately formatted, such as prescribed by Standard NATO Agreement (STANAG) 4545 or the National Imagery Transmission Format, version 2.1 (NITF 2.1). Ground activity sensors suffer from false alarms due to meteorological or biological activity. The addition of imaging allows the analyst to differentiate valid threats from nuisance alarms. Images are prescreened based on target size and temperature difference relative to the background. The combination of video motion detection based on thermal imaging with seismic, magnetic or passive IR sensing modalities improves data quality through multi-phenomenon combinatorial logic. The ground-based images having a nominally vertical aspect are transformed to the horizontal geospatial domain for exploitation and correlation of UGS imagery with other ISR data and for efficient archive and retrieval purposes. The description of an UGS system utilized and solutions that were developed and implemented during an experiment to correlate and fuse IR still imagery with ground moving target information, forming real-time, actionable, coalition intelligence, are presented.

  9. Dominant pulse simulation of near fault ground motions

    NASA Astrophysics Data System (ADS)

    Hoseini Vaez, S. R.; Sharbatdar, M. K.; Ghodrati Amiri, G.; Naderpour, H.; Kheyroddin, A.

    2013-06-01

    In this study, a new mathematical model is developed composed of two parts, including harmonic and polynomial expressions for simulating the dominant velocity pulse of near fault ground motions. Based on a proposed velocity function, the corresponding expressions for the ground acceleration and displacement time histories are also derived. The proposed model is then fitted using some selected pulse-like near fault ground motions in the Next Generation Attenuation (NGA) project library. The new model is not only simple in form but also simulates the long-period portion of actual velocity near fault records with a high level of precision. It is shown that the proposed model-based elastic response spectra are compatible with the near fault records in the neighborhood of the prevailing frequency of the pulse. The results indicate that the proposed model adequately simulates the components of the time histories. Finally, the energy of the proposed pulse was compared with the energy of the actual record to confirm the compatibility.

  10. Establishment of Antakya Basin Strong Ground Motion Monitoring System

    NASA Astrophysics Data System (ADS)

    Durukal, E.; Özel, O.; Bikce, M.; Geneş, M. C.; Kacın, S.; Erdik, M.; Safak, E.; Över, S.

    2009-04-01

    Turkey is located in one of the most active earthquake zones of the world. The cities located along the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF) are exposed to significant earthquake hazard. The Hatay province near the southern terminus of the EAF has always experienced a significant seismic activity, since it is on the intersection of the northernmost segment of Dead Sea Fault Zone coming from the south, with the Cyprean Arc approaching from south-west. Historical records extending over the last 2000 years indicate that Antakya, founded in the 3rd century B.C., is effected by intensity IX-X earthquakes every 150 years. In the region, the last destructive earthquake occurred in 1872. Destructive earthquakes should be expected in the region in the near future similar to the ones that occurred in the past. The strong response of sedimentary basins to seismic waves was largely responsible for the damage produced by the devastating earthquakes of 1985 Michoacan Earthquake which severely damaged parts of Mexico City, and the 1988 Spitak Earthquake which destroyed most of Leninakan, Armenia. Much of this devastating response was explained by the conversion of seismic body waves to surface waves at the sediment/rock contacts of sedimentary basins. "Antakya Basin Strong Ground Motion Monitoring System" is set up with the aim of monitoring the earthquake response of the Antakya Basin, contributing to our understanding of basin response, contributing to earthquake risk assessment of Antakya, monitoring of regional earthquakes and determining the effects of local and regional earthquakes on the urban environment of Antakya. The soil properties beneath the strong motion stations (S-Wave velocity structure and dominant soil frequency) are determined by array measurements that involve broad-band seismometers. The strong motion monitoring system consists of six instruments installed in small buildings. The stations form a straight line along the short axis

  11. Ground motions estimates for a cascadia earthquake from liquefaction evidence

    USGS Publications Warehouse

    Dickenson, S.E.; Obermeier, S.F.

    1998-01-01

    Paleoseismic studies conducted in the coastal regions of the Pacific Northwest in the past decade have revealed evidence of crustal downdropping and subsequent tsunami inundation, attributable to a large earthquake along the Cascadia subduction zone which occurred approximately 300 years ago, and most likely in 1700 AD. In order to characterize the severity of ground motions from this earthquake, we report on results of a field search for seismically induced liquefaction features. The search was made chiefly along the coastal portions of several river valleys in Washington, rivers along the central Oregon coast, as well as on islands in the Columbia River of Oregon and Washington. In this paper we focus only on the results of the Columbia River investigation. Numerous liquefaction features were found in some regions, but not in others. The regional distribution of liquefaction features is evaluated as a function of geologic and geotechnical factors at each site in order to estimate the intensity of ground shaking.

  12. Thunder-induced ground motions: 2. Site characterization

    NASA Astrophysics Data System (ADS)

    Lin, Ting-L.; Langston, Charles A.

    2009-04-01

    Thunder-induced ground motion, near-surface refraction, and Rayleigh wave dispersion measurements were used to constrain near-surface velocity structure at an unconsolidated sediment site. We employed near-surface seismic refraction measurements to first define ranges for site structure parameters. Air-coupled and hammer-generated Rayleigh wave dispersion curves were used to further constrain the site structure by a grid search technique. The acoustic-to-seismic coupling is modeled as an incident plane P wave in a fluid half-space impinging into a solid layered half-space. We found that the infrasound-induced ground motions constrained substrate velocities and the average thickness and velocities of the near-surface layer. The addition of higher-frequency near-surface Rayleigh waves produced tighter constraints on the near-surface velocities. This suggests that natural or controlled airborne pressure sources can be used to investigate the near-surface site structures for earthquake shaking hazard studies.

  13. Ground-motion signature of dynamic ruptures on rough faults

    NASA Astrophysics Data System (ADS)

    Mai, P. Martin; Galis, Martin; Thingbaijam, Kiran K. S.; Vyas, Jagdish C.

    2016-04-01

    Natural earthquakes occur on faults characterized by large-scale segmentation and small-scale roughness. This multi-scale geometrical complexity controls the dynamic rupture process, and hence strongly affects the radiated seismic waves and near-field shaking. For a fault system with given segmentation, the question arises what are the conditions for producing large-magnitude multi-segment ruptures, as opposed to smaller single-segment events. Similarly, for variable degrees of roughness, ruptures may be arrested prematurely or may break the entire fault. In addition, fault roughness induces rupture incoherence that determines the level of high-frequency radiation. Using HPC-enabled dynamic-rupture simulations, we generate physically self-consistent rough-fault earthquake scenarios (M~6.8) and their associated near-source seismic radiation. Because these computations are too expensive to be conducted routinely for simulation-based seismic hazard assessment, we thrive to develop an effective pseudo-dynamic source characterization that produces (almost) the same ground-motion characteristics. Therefore, we examine how variable degrees of fault roughness affect rupture properties and the seismic wavefield, and develop a planar-fault kinematic source representation that emulates the observed dynamic behaviour. We propose an effective workflow for improved pseudo-dynamic source modelling that incorporates rough-fault effects and its associated high-frequency radiation in broadband ground-motion computation for simulation-based seismic hazard assessment.

  14. Predictions of high-frequency ground-motion in Taiwan based on weak motion data

    NASA Astrophysics Data System (ADS)

    D'Amico, Sebastiano; Akinci, Aybige; Malagnini, Luca

    2012-04-01

    Following a recent paper we use weak-motion waveforms to calibrate a model for the prediction of earthquake-induced ground-motion in Taiwan, in the 0.25-5.0 Hz frequency range, valid up to Mw 7.6. The excitation/attenuation model is given in terms of frequency-dependent seismic wave attenuation, Qs(f), geometrical spreading, g(r), a magnitude-dependent stress parameters Δσ for the excitation terms, and a site term for each seismic station used in the study. A set of weak-motion data was gathered from about 170 aftershocks of the Chi-Chi earthquake, Mw 7.6, of 1999 September 20, (17:47 UTC), recorded by 10 broad-band seismic stations. The moment magnitudes of the registered aftershocks ranged from Mw 3.0 to 6.5, and the hypocentral distances from a few kilometres to about 250 km. A frequency-dependent crustal quality factor, Q(f) = 350f0.32, was obtained, to be coupled with the geometrical spreading function Earthquake-related excitation spectra were calibrated over our empirical results by using a magnitude-dependent Brune model with a stress drop value of Δσ= 8.0 ± 1.0 MPa for the largest event of Mw 6.5 in our data set and with a near surface attenuation parameter of κ= 0.05 s. Results on region-specific crustal attenuation and source scaling were used to generate stochastic simulations both for point-source and extended-fault ruptures through the computer codes: Stochastic Model SIMulation, SMSIM and Extended-Fault Model Simulation, EXSIM. The absolute peak ground accelerations (PGA), peak ground velocities (PGV) and 5 per cent-damped Spectral Accelerations (SA) at three different frequencies, 0.33 Hz, 1.0 Hz and 3.0 Hz for several magnitudes and distance ranges were predicted at large magnitudes, well beyond magnitude Mw 6.5, the upper limit for the events of our

  15. Attenuation of ground-motion spectral amplitudes in southeastern Australia

    USGS Publications Warehouse

    Allen, T.I.; Cummins, P.R.; Dhu, T.; Schneider, J.F.

    2007-01-01

    A dataset comprising some 1200 weak- and strong-motion records from 84 earthquakes is compiled to develop a regional ground-motion model for southeastern Australia (SEA). Events were recorded from 1993 to 2004 and range in size from moment magnitude 2.0 ??? M ??? 4.7. The decay of vertical-component Fourier spectral amplitudes is modeled by trilinear geometrical spreading. The decay of low-frequency spectral amplitudes can be approximated by the coefficient of R-1.3 (where R is hypocentral distance) within 90 km of the seismic source. From approximately 90 to 160 km, we observe a transition zone in which the seismic coda are affected by postcritical reflections from midcrustal and Moho discontinuities. In this hypocentral distance range, geometrical spreading is approximately R+0.1. Beyond 160 km, low-frequency seismic energy attenuates rapidly with source-receiver distance, having a geometrical spreading coefficient of R-1.6. The associated regional seismic-quality factor can be expressed by the polynomial: log Q(f) = 3.66 - 1.44 log f + 0.768 (log f)2 + 0.058 (log f)3 for frequencies 0.78 ??? f ??? 19.9 Hz. Fourier spectral amplitudes, corrected for geometrical spreading and anelastic attenuation, are regressed with M to obtain quadratic source scaling coefficients. Modeled vertical-component displacement spectra fit the observed data well. Amplitude residuals are, on average, relatively small and do not vary with hypocentral distance. Predicted source spectra (i.e., at R = 1 km) are consistent with eastern North American (ENA) Models at low frequencies (f less than approximately 2 Hz) indicating that moment magnitudes calculated for SEA earthquakes are consistent with moment magnitude scales used in ENA over the observed magnitude range. The models presented represent the first spectral ground-motion prediction equations develooed for the southeastern Australian region. This work provides a useful framework for the development of regional ground-motion relations

  16. Mobility and dynamics modeling for unmanned ground vehicle motion planning

    NASA Astrophysics Data System (ADS)

    Witus, Gary

    1999-07-01

    This paper presents an approach to modeling unmanned ground vehicle (UGV) mobility performance and vehicle dynamics for evaluating the feasibility and cost of alternative motion plans. Feasibility constraints include power, traction, and roll stability limits. Sensor stabilization performance is considered in a system-level constraint requiring that the obstacle detection distance exceed the stopping distance. Mission time and power requirements are inputs to a multi- attribute cost function for planning under uncertainty. The modeling approach combines a theoretical first-principles mathematical model with an empirical knowledge-based model. The first-principles model predicts performance in an idealized deterministic environment. On-board vehicle dynamics control, for dynamic load balancing and traction management, legitimize some of the simplifying assumptions. The knowledge- based model uses historical relationships to predict the mean and variance of total system performance accounting for the contributions of unplanned reactive behaviors, local terrain variations, and vehicle response transients.

  17. Broadband ground-motion simulation using a hybrid approach

    USGS Publications Warehouse

    Graves, R.W.; Pitarka, A.

    2010-01-01

    This paper describes refinements to the hybrid broadband ground-motion simulation methodology of Graves and Pitarka (2004), which combines a deterministic approach at low frequencies (f 1 Hz). In our approach, fault rupture is represented kinematically and incorporates spatial heterogeneity in slip, rupture speed, and rise time. The prescribed slip distribution is constrained to follow an inverse wavenumber-squared fall-off and the average rupture speed is set at 80% of the local shear-wave velocity, which is then adjusted such that the rupture propagates faster in regions of high slip and slower in regions of low slip. We use a Kostrov-like slip-rate function having a rise time proportional to the square root of slip, with the average rise time across the entire fault constrained empirically. Recent observations from large surface rupturing earthquakes indicate a reduction of rupture propagation speed and lengthening of rise time in the near surface, which we model by applying a 70% reduction of the rupture speed and increasing the rise time by a factor of 2 in a zone extending from the surface to a depth of 5 km. We demonstrate the fidelity of the technique by modeling the strong-motion recordings from the Imperial Valley, Loma Prieta, Landers, and Northridge earthquakes.

  18. Comparison of Nonlinear Model Results Using Modified Recorded and Synthetic Ground Motions

    SciTech Connect

    Robert E. Spears; J. Kevin Wilkins

    2011-11-01

    A study has been performed that compares results of nonlinear model runs using two sets of earthquake ground motion time histories that have been modified to fit the same design response spectra. The time histories include applicable modified recorded earthquake ground motion time histories and synthetic ground motion time histories. The modified recorded earthquake ground motion time histories are modified from time history records that are selected based on consistent magnitude and distance. The synthetic ground motion time histories are generated using appropriate Fourier amplitude spectrums, Arias intensity, and drift correction. All of the time history modification is performed using the same algorithm to fit the design response spectra. The study provides data to demonstrate that properly managed synthetic ground motion time histories are reasonable for use in nonlinear seismic analysis.

  19. Software for inference of dynamic ground strains and rotations and their errors from short baseline array observations of ground motions

    USGS Publications Warehouse

    Spudich, Paul; Fletcher, Jon B.

    2009-01-01

    In two previous articles we presented a formulation for inferring the strains and rotations of the ground beneath a seismic array having a finite footprint. In this article we derive expressions for the error covariance matrices of the inferred strains and rotations, and we present software for the calculation of ground strains, rotations, and their variances from short baseline array ground-motion data.

  20. SISMA (Site of Italian Strong Motion Accelerograms): a Web-Database of Ground Motion Recordings for Engineering Applications

    SciTech Connect

    Scasserra, Giuseppe; Lanzo, Giuseppe; D'Elia, Beniamino; Stewart, Jonathan P.

    2008-07-08

    The paper describes a new website called SISMA, i.e. Site of Italian Strong Motion Accelerograms, which is an Internet portal intended to provide natural records for use in engineering applications for dynamic analyses of structural and geotechnical systems. SISMA contains 247 three-component corrected motions recorded at 101 stations from 89 earthquakes that occurred in Italy in the period 1972-2002. The database of strong motion accelerograms was developed in the framework of a joint project between Sapienza University of Rome and University of California at Los Angeles (USA) and is described elsewhere. Acceleration histories and pseudo-acceleration response spectra (5% damping) are available for download from the website. Recordings can be located using simple search parameters related to seismic source and the recording station (e.g., magnitude, V{sub s30}, etc) as well as ground motion characteristics (e.g. peak ground acceleration, peak ground velocity, peak ground displacement, Arias intensity, etc.)

  1. Statistical modeling of ground motion relations for seismic hazard analysis

    NASA Astrophysics Data System (ADS)

    Raschke, Mathias

    2013-10-01

    We introduce a new approach for ground motion relations (GMR) in the probabilistic seismic hazard analysis (PSHA), being influenced by the extreme value theory of mathematical statistics. Therein, we understand a GMR as a random function. We derive mathematically the principle of area equivalence, wherein two alternative GMRs have an equivalent influence on the hazard if these GMRs have equivalent area functions. This includes local biases. An interpretation of the difference between these GMRs (an actual and a modeled one) as a random component leads to a general overestimation of residual variance and hazard. Beside this, we discuss important aspects of classical approaches and discover discrepancies with the state of the art of stochastics and statistics (model selection and significance, test of distribution assumptions, extreme value statistics). We criticize especially the assumption of logarithmic normally distributed residuals of maxima like the peak ground acceleration (PGA). The natural distribution of its individual random component (equivalent to exp( ɛ 0) of Joyner and Boore, Bull Seism Soc Am 83(2):469-487, 1993) is the generalized extreme value. We show by numerical researches that the actual distribution can be hidden and a wrong distribution assumption can influence the PSHA negatively as the negligence of area equivalence does. Finally, we suggest an estimation concept for GMRs of PSHA with a regression-free variance estimation of the individual random component. We demonstrate the advantages of event-specific GMRs by analyzing data sets from the PEER strong motion database and estimate event-specific GMRs. Therein, the majority of the best models base on an anisotropic point source approach. The residual variance of logarithmized PGA is significantly smaller than in previous models. We validate the estimations for the event with the largest sample by empirical area functions, which indicate the appropriate modeling of the GMR by an anisotropic

  2. Ground motions at the outermost limits of seismically triggered landslides

    USGS Publications Warehouse

    Jibson, Randall W.; Harp, Edwin L.

    2016-01-01

    Over the last few decades, we and our colleagues have conducted field investigations in which we mapped the outermost limits of triggered landslides in four earthquakes: 1987 Whittier Narrows, California (M 5.9), 1987 Superstition Hills, California (M 6.5), 1994 Northridge, California (M 6.7), and 2011 Mineral, Virginia (M 5.8). In an additional two earthquakes, 1976 Guatemala (M 7.5) and 1983 Coalinga, California (M 6.5), we determined limits using high‐resolution aerial‐photographic interpretation in conjunction with more limited ground investigation. Limits in these earthquakes were defined by the locations of the very smallest failures (<1  m3) from the most susceptible slopes that can be identified positively as having been triggered by earthquake shaking. Because we and our colleagues conducted all of these investigations, consistent methodology and criteria were used in determining limits. In the six earthquakes examined, we correlated the outermost landslide limits with peak ground accelerations (PGAs) from ShakeMap models of each earthquake. For the four earthquakes studied by field investigation, the minimum PGA values associated with farthest landslide limits ranged from 0.02g to 0.08g. The range for the two earthquakes investigated using aerial‐photographic interpretations was 0.05–0.11g. Although PGA values at landslide limits depend on several factors, including material strength, topographic amplification, and hydrologic conditions, these values provide an empirically useful lower limiting range of PGA needed to trigger the smallest failures on very susceptible slopes. In a well‐recorded earthquake, this PGA range can be used to identify an outer boundary within which we might expect to find landsliding; in earthquakes that are not well recorded, mapping the outermost landslide limits provides a useful clue about ground‐motion levels at the mapped limits.

  3. Engineering characterization of ground motion. Task I. Effects of characteristics of free-field motion on structural response

    SciTech Connect

    Kennedy, R.P.; Short, S.A.; Merz, K.L.; Tokarz, F.J.; Idriss, I.M.; Power, M.S.; Sadigh, K.

    1984-05-01

    This report presents the results of the first task of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. The overall objective of this study is to develop recommendations for methods for selecting design response spectra or acceleration time histories to be used to characterize motion at the foundation level of nuclear power plants. Task I of the study develops a basis for selecting design response spectra, taking into account the characteristics of free-field ground motion found to be significant in causing structural damage.

  4. Analytic model for surface ground motion with spall induced by underground nuclear tests

    SciTech Connect

    MacQueen, D.H.

    1982-04-01

    This report provides a detailed presentation and critique of a model used to characterize the surface ground motion following a contained, spalling underground nuclear explosion intended for calculation of the resulting atmospheric acoustic pulse. Some examples of its use are included. Some discussion of the general approach of ground motion model parameter extraction, not dependent on the specific model, is also presented.

  5. Discussion on the influence of truncation of ground motion residual distribution on probabilistic seismic hazard assessment

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Gao, Mengtan; Chen, Kun; Huang, Bei

    2011-09-01

    Recent studies on assessment of a very low annual probability of exceeding (APE) ground motions, 10-4 or less, have highlighted the importance of the upper bound of ground motions when very low probability results are acquired. The truncation level adopted in probabilistic seismic hazard analysis (PSHA) should be determined by an aleatory uncertainty model (i.e., distribution model) of ground motions and the possible maximum and minimum ground motion values of a specific earthquake. However, at the present time, it is impossible to establish the upper bound model for ground motions based on the source characteristics and/or ground motion propagation. McGuire suggested a truncation level be fixed at a number of ɛ = 6, or the distribution of residuals be truncated in such a manner that site intensity cannot be greater than the epicenter intensity. This study aims to find a reasonable and feasible truncation level to be used in PSHA when the physical mechanism is not available to find the extreme ground motion. A mathematical analysis of the influence of the truncation level on PSHA, case studies of sites in different seismotectonic settings, and a distribution analysis of ground motion residuals are conducted in this study. It is concluded that ɛ = 4 is the minimum acceptable value for engineering applications for APEs within 0.002 to 10-4, and for low APEs, such as 10-5 and 10-6, the value of ɛ should be no less than 5 in most regions of China.

  6. Losses to single-family housing from ground motions in the 1994 Northridge, California, earthquake

    USGS Publications Warehouse

    Wesson, R.L.; Perkins, D.M.; Leyendecker, E.V.; Roth, R.J., Jr.; Petersen, M.D.

    2004-01-01

    The distributions of insured losses to single-family housing following the 1994 Northridge, California, earthquake for 234 ZIP codes can be satisfactorily modeled with gamma distributions. Regressions of the parameters in the gamma distribution on estimates of ground motion, derived from ShakeMap estimates or from interpolated observations, provide a basis for developing curves of conditional probability of loss given a ground motion. Comparison of the resulting estimates of aggregate loss with the actual aggregate loss gives satisfactory agreement for several different ground-motion parameters. Estimates of loss based on a deterministic spatial model of the earthquake ground motion, using standard attenuation relationships and NEHRP soil factors, give satisfactory results for some ground-motion parameters if the input ground motions are increased about one and one-half standard deviations above the median, reflecting the fact that the ground motions for the Northridge earthquake tended to be higher than the median ground motion for other earthquakes with similar magnitude. The results give promise for making estimates of insured losses to a similar building stock under future earthquake loading. ?? 2004, Earthquake Engineering Research Institute.

  7. Engineering characterization of ground motion. Task II. Effects of ground motion characteristics on structural response considering localized structural nonlinearities and soil-structure interaction effects. Volume 2

    SciTech Connect

    Kennedy, R.P.; Kincaid, R.H.; Short, S.A.

    1985-03-01

    This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. Task I of the study, which is presented in NUREG/CR-3805, Vol. 1, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in four parts: (1) effects of ground motion characteristics on structural response of a typical PWR reactor building with localized nonlinearities and soil-structure interaction effects; (2) empirical data on spatial variations of earthquake ground motion; (3) soil-structure interaction effects on structural response; and (4) summary of conclusions and recommendations based on Tasks I and II studies. This report presents the results of the first part of Task II. The results of the other parts will be presented in NUREG/CR-3805, Vols. 3 to 5.

  8. 2001 Bhuj, India, earthquake engineering seismoscope recordings and Eastern North America ground-motion attenuation relations

    USGS Publications Warehouse

    Cramer, C.H.; Kumar, A.

    2003-01-01

    Engineering seismoscope data collected at distances less than 300 km for the M 7.7 Bhuj, India, mainshock are compatible with ground-motion attenuation in eastern North America (ENA). The mainshock ground-motion data have been corrected to a common geological site condition using the factors of Joyner and Boore (2000) and a classification scheme of Quaternary or Tertiary sediments or rock. We then compare these data to ENA ground-motion attenuation relations. Despite uncertainties in recording method, geological site corrections, common tectonic setting, and the amount of regional seismic attenuation, the corrected Bhuj dataset agrees with the collective predictions by ENA ground-motion attenuation relations within a factor of 2. This level of agreement is within the dataset uncertainties and the normal variance for recorded earthquake ground motions.

  9. Strong ground motion prediction for southwestern China from small earthquake records

    NASA Astrophysics Data System (ADS)

    Tao, Z. R.; Tao, X. X.; Cui, A. P.

    2015-09-01

    For regions lack of strong ground motion records, a method is developed to predict strong ground motion by small earthquake records from local broadband digital earthquake networks. Sichuan and Yunnan regions, located in southwestern China, are selected as the targets. Five regional source and crustal medium parameters are inversed by micro-Genetic Algorithm. These parameters are adopted to predict strong ground motion for moment magnitude (Mw) 5.0, 6.0 and 7.0. Strong ground motion data are compared with the results, most of the result pass through ideally the data point plexus, except the case of Mw 7.0 in Sichuan region, which shows an obvious slow attenuation. For further application, this result is adopted in probability seismic hazard assessment (PSHA) and near-field strong ground motion synthesis of the Wenchuan Earthquake.

  10. Synthetic strong ground motions for engineering design utilizing empirical Green`s functions

    SciTech Connect

    Hutchings, L.J.; Jarpe, S.P.; Kasameyer, P.W.; Foxall, W.

    1996-04-11

    We present a methodology for developing realistic synthetic strong ground motions for specific sites from specific earthquakes. We analyzed the possible ground motion resulting from a M = 7.25 earthquake that ruptures 82 km of the Hayward fault for a site 1.4 km from the fault in the eastern San Francisco Bay area. We developed a suite of 100 rupture scenarios for the Hayward fault earthquake and computed the corresponding strong ground motion time histories. We synthesized strong ground motion with physics-based solutions of earthquake rupture and applied physical bounds on rupture parameters. By having a suite of rupture scenarios of hazardous earthquakes for a fixed magnitude and identifying the hazard to the site from the statistical distribution of engineering parameters, we introduce a probabilistic component into the deterministic hazard calculation. Engineering parameters of synthesized ground motions agree with those recorded from the 1995 Kobe, Japan and the 1992 Landers, California earthquakes at similar distances and site geologies.

  11. The 2011 Mineral, VA M5.8 Earthquake Ground Motions and Stress Drop: An Important Contribution to the NGA East Ground Motion Database

    NASA Astrophysics Data System (ADS)

    Cramer, C. H.; Kutliroff, J.; Dangkua, D.

    2011-12-01

    The M5.8 Mineral, Virginia earthquake of August 23, 2011 is the largest instrumentally recorded earthquake in eastern North America since the 1988 M5.9 Saguenay, Canada earthquake. Historically, a similar magnitude earthquake occurred on May 31, 1897 at 18:58 UCT in western Virginia west of Roanoke. Paleoseismic evidence for larger magnitude earthquakes has also been found in the central Virginia region. The Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), is ongoing at the Pacific Earthquake Engineering Research Center funded by the U.S. Nuclear Regulatory Commission, the U.S. Geological Survey, the Electric Power Research Institute, and the U.S. Department of Energy. The available recordings from the M5.8 Virginia are being added to the NGA East ground motion database. Close in (less than 100 km) strong motion recordings are particularly interesting for both ground motion and stress drop estimates as most close-in broadband seismometers clipped on the mainshock. A preliminary estimate for earthquake corner frequency for the M5.8 Virginia earthquake of ~0.7 Hz has been obtained from a strong motion record 57 km from the mainshock epicenter. For a M5.8 earthquake this suggests a Brune stress drop of ~300 bars for the Virginia event. Very preliminary comparisons using accelerometer data suggest the ground motions from the M5.8 Virginia earthquake agree well with current ENA ground motion prediction equations (GMPEs) at short periods (PGA, 0.2 s) and are below the GMPEs at longer periods (1.0 s), which is the same relationship seen from other recent M5 ENA earthquakes. We will present observed versus GMPE ground motion comparisons for all the ground motion observations and stress drop estimates from strong motion recordings at distances less than 100 km. A review of the completed NGA East ENA ground motion database will also be provided.

  12. Strong Ground-Motion Prediction in Seismic Hazard Analysis: PEGASOS and Beyond

    NASA Astrophysics Data System (ADS)

    Scherbaum, F.; Bommer, J. J.; Cotton, F.; Bungum, H.; Sabetta, F.

    2005-12-01

    The SSHAC Level 4 approach to probabilistic seismic hazard analysis (PSHA), which could be considered to define the state-of-the-art in PSHA using multiple expert opinions, has been fully applied only twice, firstly in the multi-year Yucca Mountain study and subsequently (2002-2004) in the PEGASOS project. The authors of this paper participated as ground-motion experts in this latter project, the objective of which was comprehensive seismic hazard analysis for four nuclear power plant sites in Switzerland, considering annual exceedance frequencies down to 1/10000000. Following SSHAC procedure, particular emphasis was put on capturing both the aleatory and epistemic uncertainties. As a consequence, ground motion prediction was performed by combining several empirical ground motion models within a logic tree framework with the weights on each logic tree branch expressing the personal degree-of-belief of each ground-motion expert. In the present paper, we critically review the current state of ground motion prediction methodology in PSHA in particular for regions of low seismicity. One of the toughest lessons from PEGASOS was that in systematically and rigorously applying the laws of uncertainty propagation to all of the required conversions and adjustments of ground motion models, a huge price has to be paid in an ever-growing aleatory variability. Once this path has been followed, these large sigma values will drive the hazard, particularly for low annual frequencies of exceedance. Therefore, from a post-PEGASOS perspective, the key issues in the context of ground-motion prediction for PSHA for the near future are to better understand the aleatory variability of ground motion and to develop suites of ground-motion prediction equations that employ the same parameter definitions. The latter is a global rather than a regional challenge which might be a desirable long-term goal for projects similar to the PEER NGA (Pacific Earthquake Engineering Research Center, Next

  13. Seismic Safety Program: Ground motion and structural response

    SciTech Connect

    Not Available

    1993-05-01

    In 1964, John A. Blume & Associates Research Division (Blume) began a broad-range structural response program to assist the Nevada Operations Office of the US Atomic Energy Commission (AEC) in ensuring the continued safe conduct of underground nuclear detonation testing at the Nevada Test Site (NTS) and elsewhere. Blume`s long experience in earthquake engineering provided a general basis for the program, but much more specialized knowledge was required for the AEC`s purposes. Over the next 24 years Blume conducted a major research program to provide essential understanding of the detailed nature of the response of structures to dynamic loads such as those imposed by seismic wave propagation. The program`s results have been embodied in a prediction technology which has served to provide reliable advanced knowledge of the probable effects of seismic ground motion on all kinds of structures, for use in earthquake engineering and in building codes as well as for the continuing needs of the US Department of Energy`s Nevada Operations Office (DOE/NV). This report is primarily an accounting of the Blume work, beginning with the setting in 1964 and the perception of the program needs as envisioned by Dr. John A. Blume. Subsequent chapters describe the structural response program in detail and the structural prediction procedures which resulted; the intensive data acquisition program which, as is discussed at some length, relied heavily on the contributions of other consultant-contractors in the DOE/NV Seismic Safety Support Program; laboratory and field studies to provide data on building elements and structures subjected to dynamic loads from sources ranging from testing machines to earthquakes; structural response activities undertaken for testing at the NTS and for off-NTS underground nuclear detonations; and concluding with an account of corollary studies including effects of natural forces and of related studies on building response.

  14. Testing the Double Corner Source Spectral Model for Long- and Short-Period Ground Motion Simulations

    NASA Astrophysics Data System (ADS)

    Miyake, H.; Koketsu, K.

    2010-12-01

    The omega-squared source model with a single corner frequency is widely used in the earthquake source analyses and ground motion simulations. Recent studies show that the Brune stress drop of subduction-zone earthquakes is almost half of that for crustal earthquakes for a given magnitude. On the other hand, the empirical attenuation relations and spectral analyses of seismic source and ground motions support the fact that subduction-zone earthquakes provide 1-2 times of the short-period source spectral level for crustal earthquakes. To link long- and short-period source characteristics is a crucial issue to perform broadband ground motion simulations. This discrepancy may lead the source modeling with double corner frequencies [e.g., Atkinson, 1993]. We modeled the lower corner frequency corresponding to the size of asperities generating for long-period (> 2-5 s) ground motions by the deterministic approach and the higher corner frequency corresponding to the size of strong motion generation area for short-period ground motions by the semi-empirical approach. We propose that the double corner source spectral model is expressed as a frequency-dependent source model consists of either the asperities in a long-period range or the strong motion generation area in a short-period range and the surrounding background area inside the total rupture area. The characterized source model has been the potential to reproduce fairly well the rupture directivity pulses seen in the observed ground motions. We explore the applicability of the double corner source spectral model to broadband ground motion simulations for the 1978 Mw 7.6 Miyagi-oki and 2003 Mw 8.3 Tokachi-oki earthquakes along the Japan Trench. For both cases, the double corner source spectral model, where the size and stress drop for strong motion generation areas are respectively half and double of those for asperities, worked well to reproduce ground motion time histories and seismic intensity distribution.

  15. Source Scaling and Ground Motion of the 2008 Wells, Nevada, earthquake sequence

    NASA Astrophysics Data System (ADS)

    Yoo, S.; Dreger, D. S.; Mayeda, K. M.; Walter, W. R.

    2011-12-01

    Dynamic source parameters, such as a corner frequency, stress drop, and radiated energy, are one of the most critical factors controlling ground motions at higher-frequencies (generally greater than 1 Hz), which may cause damage to nearby surface structures. Hence, scaling relation of these parameters can play an important role in assessing the seismic hazard for regions in which records of ground motions from potentially damaging earthquakes are not available. On February 21, 2008 at 14:16 (UTC), a magnitude 6 earthquake occurred near Wells, Nevada, where characterized by low rate of seismicity. For their aftershocks, a marked discrepancy between the observed and predicted ground motions from empirical ground motion prediction equation was reported (Petersen et al., 2011). To evaluate and understand these observed ground motions, we investigate the dynamic source parameters and their scaling relation for this earthquake sequence. We estimate the source parameters of the earthquakes using the coda spectral ratio method (Mayeda et al., 2007) and examine the estimates with the observed spectral accelerations at higher frequencies. From the derived source parameters and scaling relation, we compute synthetic ground motions of the earthquakes using fractal composite source model (e.g., Zeng et al., 1994) and compare these synthetic ground motions with the observed ground motions and synthetic ground motions obtained from self-similar source scaling relation. In our preliminary results, we find the stress drops of the aftershocks are systematically 2-5 times lower than a stress drop of the mainshock. This agrees well with systematic overestimation of the predicted ground motions for the aftershocks. The simulated ground motions from the coda-derived scaling relation better explains the observed both weak and strong ground motions than that of from the size independent stress drop scaling relation. Assuming that the scale dependent stress drop is real, at least in some

  16. Near field ground motion variability in kinematic simulations of the 1992 Landers earthquake

    NASA Astrophysics Data System (ADS)

    Vyas, Jagdish Chandra; Galis, Martin; Mai, Paul Martin

    2014-05-01

    We investigate near field ground motion variability due to five different kinematic rupture models inverted from observed data for 1992 Landers earthquake. The ground motion simulations are accomplished by solving the elastic equation of motion using a generalized finite-difference method (Ely et al., 2008) that handles geometric complexity of the fault, 3D variations in the medium as well as topography. Simulated waveforms are calibrated against near-field strong-motion recordings. We then analyze a large data-set of ground-motions computed at 2000 sites, binned with respect to distance and azimuth to compute mean and standard deviation of peak ground velocity (PGV) and pseudo spectral acceleration (PSA) for all five source models. We consider 1D-velocity structures as used in the source inversions, and honor the geometrical complexity due to segmentation of the rupture models. Our simulations reveal that ground motion variability is reduced as the distance from the fault increases. Variability in the kinematic sources has considerable impact on the resulting shaking variability, although the five source models considered are derived by inversion of seismic and/or geodetic data. Simulated mean PSA and its standard deviation are larger compared to empirical estimates using the ground-motion prediction equation (GMPE) of Boore and Atkinson (2008), whereas simulated PGV are comparable to GMPE estimates. In addition, we find that intra-event ground motion variability is large both in forward and backward directivity region, strongest in the backward region, and smallest in the fault perpendicular direction. We then examine ground-motion variability with respect to directivity effects, due to a combination of rupture propagation and radiation pattern. The comparison of our simulations with and without Spudich and Chiou (2008) directivity corrections to Boore and Atkinson (2008) predictions indicates that slip heterogeneity is the key contributor to ground motion

  17. A Study of Site Effect (Vs30) for Attenuation Relations of Ground Motion in Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, K.; TEC, Taiwan Earthquake Research Center

    2011-12-01

    An evaluation of seismic hazards requires an estimate of the expected ground motion at the site of interest. The most common means of estimating this ground motion in engineering practice is the use of an attenuation relation. A number of developments have arisen recently to suggest that a new generation of attenuation relationships is warranted. The project named Next Generation Attenuation of Ground Motions (NGA) Project was developed by Pacific Earthquake Engineering Research Center (PEER) in response to a core objective: reducing uncertainty in earthquake ground motion estimation. This objective reflects recognition from industry sponsors that improvements in earthquake ground motion estimation will result in significant cost savings and will result in improved system performance in the event of a large earthquake. The Central Weather Bureau has implemented the Taiwan Strong Motion Instrumentation Program (TSMIP) to collect high-quality instrumental recordings of strong earthquake shaking. It is necessary for us to study the strong ground motion characteristics in Taiwan. Further analyses using a good quality data base are required to derive the next generation attenuation of ground motion in Taiwan. In this study, the site response factor, the mean shear-wave velocity over the first 30 m (VS30), is incorporated in the present ground motion prediction models. Such prediction models will result in more realistic peak ground motion estimates for assessment of seismic hazard potential. These results provide an important database for the site evaluation of critical facilities in those relatively high earthquake hazard potential regions and will be helpful for the plan of land-using.

  18. What Do Data Used to Develop Ground-Motion Prediction Equations Tell Us About Motions Near Faults?

    NASA Astrophysics Data System (ADS)

    Boore, David M.

    2014-11-01

    A large database of ground motions from shallow earthquakes occurring in active tectonic regions around the world, recently developed in the Pacific Earthquake Engineering Center's NGA-West2 project, has been used to investigate what such a database can say about the properties and processes of crustal fault zones. There are a relatively small number of near-rupture records, implying that few recordings in the database are within crustal fault zones, but the records that do exist emphasize the complexity of ground-motion amplitudes and polarization close to individual faults. On average over the whole data set, however, the scaling of ground motions with magnitude at a fixed distance, and the distance dependence of the ground motions, seem to be largely consistent with simple seismological models of source scaling, path propagation effects, and local site amplification. The data show that ground motions close to large faults, as measured by elastic response spectra, tend to saturate and become essentially constant for short periods. This saturation seems to be primarily a geometrical effect, due to the increasing size of the rupture surface with magnitude, and not due to a breakdown in self similarity.

  19. What do data used to develop ground-motion prediction equations tell us about motions near faults?

    USGS Publications Warehouse

    Boore, David M.

    2014-01-01

    A large database of ground motions from shallow earthquakes occurring in active tectonic regions around the world, recently developed in the Pacific Earthquake Engineering Center’s NGA-West2 project, has been used to investigate what such a database can say about the properties and processes of crustal fault zones. There are a relatively small number of near-rupture records, implying that few recordings in the database are within crustal fault zones, but the records that do exist emphasize the complexity of ground-motion amplitudes and polarization close to individual faults. On average over the whole data set, however, the scaling of ground motions with magnitude at a fixed distance, and the distance dependence of the ground motions, seem to be largely consistent with simple seismological models of source scaling, path propagation effects, and local site amplification. The data show that ground motions close to large faults, as measured by elastic response spectra, tend to saturate and become essentially constant for short periods. This saturation seems to be primarily a geometrical effect, due to the increasing size of the rupture surface with magnitude, and not due to a breakdown in self similarity.

  20. Kinematic source models for long-period ground motion simulations of megathrust earthquakes: validation against ground motion data for the 2003 Tokachi-oki earthquake

    NASA Astrophysics Data System (ADS)

    Iwaki, Asako; Maeda, Takahiro; Morikawa, Nobuyuki; Aoi, Shin; Fujiwara, Hiroyuki

    2016-06-01

    In this study, a method for simulating the ground motion of megathrust earthquakes at periods of approximately 2 s and longer was validated by using the characterized source model combined with multi-scale spatial heterogeneity. Source models for the M W 8.3, 2003 Tokachi-oki earthquake were constructed, and ground motion simulations were conducted to test their performance. First, a characterized source model was generated based on a source model obtained from waveform inversion analysis. Then, multi-scale heterogeneity was added to the spatial distribution of several source parameters to yield a heterogeneous source model. An investigation of the Fourier spectra and 5 % damped velocity response spectra of the simulated and observed ground motions demonstrated that adding multi-scale heterogeneity to the spatial distributions of the slip, rupture velocity, and rake angle of the characterized source model is an effective method for constructing a source model that explains the ground motion at periods of 2-20 s. It was also revealed how the complexity of the parameters affects the resulting ground motion. The complexity of the rupture velocity had the largest influence among the three parameters.

  1. An evaluation of the strong ground motion recorded during the May 1, 2003 Bingol Turkey, earthquake

    USGS Publications Warehouse

    Akkar, Sinan; Boore, David M.; Gulkan, Polat

    2005-01-01

    An important record of ground motion from a M6.4 earthquake occurring on May 1, 2003, at epicentral and fault distances of about 12 and 9 km, respectively, was obtained at a station near the city of Bingöl, Turkey. The maximum peak ground values of 0.55g and 36 cm/s are among the largest ground-motion amplitudes recorded in Turkey. From simulations and comparisons with ground motions from other earthquakes of comparable magnitude, we conclude that the ground motion over a range of frequencies is unusually high. Site response may be responsible for the elevated ground motion, as suggested from analysis of numerous aftershock recordings from the same station. The mainshock motions have some interesting seismological features, including ramps between the P- and S-wave that are probably due to near- and intermediate-field elastic motions and strong polarisation oriented at about 39 degrees to the fault (and therefore not in the fault-normal direction). Simulations of motions from an extended rupture explain these features. The N10E component shows a high-amplitude spectral acceleration at a period of 0.15 seconds resulting in a site specific design spectrum that significantly overestimates the actual strength and displacement demands of the record. The pulse signal in the N10E component affects the inelastic spectral displacement and increases the inelastic displacement demand with respect to elastic demand for very long periods.

  2. Representation of bidirectional ground motions for design spectra in building codes

    USGS Publications Warehouse

    Stewart, Jonathan P.; Abrahamson, Norman A.; Atkinson, Gail M.; Beker, Jack W.; Boore, David M.; Bozorgnia, Yousef; Campbell, Kenneth W.; Comartin, Craig D.; Idriss, I.M.; Lew, Marshall; Mehrain, Michael; Moehle, Jack P.; Naeim, Farzad; Sabol, Thomas A.

    2011-01-01

    The 2009 NEHRP Provisions modified the definition of horizontal ground motion from the geometric mean of spectral accelerations for two components to the peak response of a single lumped mass oscillator regardless of direction. These maximum-direction (MD) ground motions operate under the assumption that the dynamic properties of the structure (e.g., stiffness, strength) are identical in all directions. This assumption may be true for some in-plan symmetric structures, however, the response of most structures is dominated by modes of vibration along specific axes (e.g., longitudinal and transverse axes in a building), and often the dynamic properties (especially stiffness) along those axes are distinct. In order to achieve structural designs consistent with the collapse risk level given in the NEHRP documents, we argue that design spectra should be compatible with expected levels of ground motion along those principal response axes. The use of MD ground motions effectively assumes that the azimuth of maximum ground motion coincides with the directions of principal structural response. Because this is unlikely, design ground motions have lower probability of occurrence than intended, with significant societal costs. We recommend adjustments to make design ground motions compatible with target risk levels.

  3. Fractal characterization and frequency properties of near-fault ground motions

    NASA Astrophysics Data System (ADS)

    Yang, Dixiong; Zhang, Changgeng

    2013-12-01

    This study explores the irregularity and complexity of strong earthquake ground motions from the perspective of fractal geometry, and constructs a relation with the frequency content of the ground motions. The box-counting fractal dimensions and five representative period parameters of near-fault ground motions from the Chi-Chi and Northridge earthquakes are calculated and compared. Numerical results indicate that the acceleration and velocity time histories of ground motions present the statistical fractal property, and the dominant pulses of near-fault ground motions have a significant influence on their box dimensions and periods. Further, the average box dimension of near-fault impulsive ground motions is smaller, and their irregular degree of wave forms is lower. Moreover, the box dimensions of ground motions reflect their frequency properties to a large extent, and can be regarded as an alternative indicator to represent their frequency content. Finally, the box dimension D of the acceleration histories shows a considerably negative correlation with the mean period T m. Meanwhile, the box dimension of the velocity histories D vel is negatively correlated with the characteristic period T c and improved characteristic period T gi.

  4. Model and parametric uncertainty in source-based kinematic models of earthquake ground motion

    USGS Publications Warehouse

    Hartzell, Stephen; Frankel, Arthur; Liu, Pengcheng; Zeng, Yuehua; Rahman, Shariftur

    2011-01-01

    Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric uncertainty for changes in rupture velocity. We find that the combined model uncertainty and random variability of the simulations is in the same range as the variability of regional empirical ground-motion data sets. The majority of the standard deviations lie between 0.5 and 0.7 natural-log units for response spectra and 0.5 and 0.8 for Fourier spectra. The estimate of model epistemic uncertainty, based on the different model predictions, lies between 0.2 and 0.4, which is about one-half of the estimates for the standard deviation of the combined model uncertainty and random variability. Parametric uncertainty, based on variation of just the average rupture velocity, is shown to be consistent in amplitude with previous estimates, showing percentage changes in ground motion from 50% to 300% when rupture velocity changes from 2.5 to 2.9 km/s. In addition, there is some evidence that mean biases can be reduced by averaging ground-motion estimates from different methods.

  5. Seismic ground motion scenarios in Lower Tagus Valley Basin

    NASA Astrophysics Data System (ADS)

    Borges, José; Torres, Ricardo; Furtado, José; Silva, Hugo; Caldeira, Bento; Pinto, Carlos; Bezzeghoud, Mourad; Carvalho, João

    2013-04-01

    Throughout its history the Lower Tagus Valley (LTV) has been struck by several earthquakes which produced important material damage and loss of lives: The 1st of November 1755 Lisbon earthquake and the 1969 earthquake (Mw=7.3), located in the SW Iberia Margin and the 1344, 1531 and 1909 (M= 6 to 7) with epicenter located inside the LTV basin. Since this region is the most highly populated region in Portugal, it is expected that an earthquake of similar magnitude of those that have occurred in the past will cause an enormous destruction and casualties. This fact makes LTV a high priority area for earthquake research in Portugal. In order to overcome the problems related to the absence of geological outcrops, low slip-rates (<0,4 mm/year) and the processes of sedimentation and erosion, we use in this work seismic reflection profiles, potential field data, soundings, wells and geological cartography to obtain a map of the main seismogenic structures and to characterize their seismic potential [1]. Moreover, a 3D structural model has been developed for de LTV based on Seismic reflection, Seismic Noise and potential field data [2,3]. In order to improve assessment of the seismic hazard in the LTV basin, we simulate long-period (0-1 Hz) ground motion time histories for a suite of scenarios earthquakes (Mw =5.5 to 7) within the basin, using fault geometries and the 3D seismic velocity structure based on the previous mentioned works. References [1] Pinto, Carlos C. (2011). Identification of Seismogenic Structures in the Lower Tagus Basin. Master Thesis, Universidade de Évora, 128 pp. [2] Torres, R.J.G., (2012). Modelo de velocidade da Bacia do Vale do Tejo: uma abordagem baseada no estudo do ruído sísmico ambiental, Master Thesis, Universidade de Évora, 83pp. [3] Furtado, J.A (2010). Confirmação do modelo da estrutura 3D do Vale Inverior do Tejo a partir de dados de ruído sísmico ambiente, Master Thesis, Universidade de Évora, 136pp.

  6. Implications of the Northridge earthquake for strong ground motions from thrust faults

    USGS Publications Warehouse

    Somerville, P.; Saikia, C.; Wald, D.; Graves, R.

    1996-01-01

    The peak accelerations recorded on alluvial sites during the Northridge earthquake were about 50% larger than the median value predicted by current empirical attenuation relations at distances less than about 30 km. This raises the question of whether the ground motions from the Northridge earthquake are anomalous for thrust events or are representative of ground motions expected in future thrust earthquakes. Since the empirical data base contains few strong-motion records close to large-thrust earthquakes, it is difficult to assess whether the Northridge ground motions are anomalous based on recorded data alone. For this reason, we have used a broadband strong-motion simulation procedure to help assess whether the ground motions were anomalous. The simulation procedure has been validated against a large body of strong-motion data from California earthquakes, and so we expect it to produce accurate estimates of ground motions for any given rupture scenario, including blind-thrust events for which no good precedent existed in the strong-motion data base until the occurrence of the Northridge earthquake. The ground motions from the Northridge earthquake and our simulations of these ground motions have a similar pattern of departure from empirical attenuation relations for thrust earthquakes: the peak accelerations are at about the 84th percentile level for distances within 20 to 30 km and follow the median level for larger distances. This same pattern of departure from empirical attenuation relations was obtained in our simulations of the peak accelerations of an Elysian Park blind-thrust event prior to the occurrence of the Northridge earthquake. Since we are able to model this pattern with broadband simulations, and had done so before the Northridge earthquake occurred, this suggests that the Northridge strong-motion records are not anomalous and are representative of ground motions close to thrust faults. Accordingly, it seems appropriate to include these

  7. Broadband Ground Motion Reconstruction for the Kanto Basin during the 1923 Kanto Earthquake

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Haruko; Yoshimi, Masayuki

    2011-03-01

    Ground motions of the 1923 Kanto Earthquake inside the Kanto Basin are numerically simulated in a wide frequency range (0-10 Hz) based on new knowledge of the earthquake's source processes, the sedimentary structure of the basin, and techniques for generating broadband source models of great earthquakes. The Kanto Earthquake remains one of the most important exemplars for ground motion prediction in Japan due to its size, faulting geometry, and location beneath the densely populated Kanto sedimentary basin. We reconstruct a broadband source model of the 1923 Kanto Earthquake from inversion results by introducing small-scale heterogeneities. The corresponding ground motions are simulated using a hybrid technique comprising the following four calculations: (1) low-frequency ground motion of the engineering basement, modeled using a finite difference method; (2) high-frequency ground motion of the engineering basement, modeled using a stochastic Green's function method; (3) total ground motion of the engineering basement (i.e. 1 + 2); and (4) ground motion at the surface in response to the total basement ground motion. We employ a recently developed three-dimensional (3D) velocity structure model of the Kanto Basin that incorporates prospecting data, microtremor observations and measurements derived from strong ground motion records. Our calculations reveal peak ground velocities (PGV) exceeding 50 cm/s in the area above the fault plane: to the south, where the fault plane is shallowest, PGV reaches 150-200 cm/s at the engineering basement and 200-250 cm/s at the surface. Intensity 7, the maximum value in the Japan Meteorological Agency's intensity scale, is calculated to have occurred widely in Sagami Bay, which corresponds well with observed house-collapse rates due to the 1923 event. The modeling reveals a pronounced forward directivity effect for the area lying above the southern, shallow part of the fault plane. The high PGV and intensity seen above the

  8. Next Generation Attenuation of Ground Motions in Ilan, Taiwan: Establishment and Analysis of Attenuation Relations for Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV)

    NASA Astrophysics Data System (ADS)

    Liu, K.

    2009-12-01

    An evaluation of seismic hazards requires an estimate of the expected ground motion at the site of interest. The most common means of estimating this ground motion in engineering practice is the use of an attenuation relation. A number of developments have arisen recently to suggest that a new generation of attenuation relationships is warranted. The project named Next Generation Attenuation of Ground Motions (NGA) Project was developed by Pacific Earthquake Engineering Research Center (PEER) in response to a core objective: reducing uncertainty in earthquake ground motion estimation. This objective reflects recognition from industry sponsors that improvements in earthquake ground motion estimation will result in significant cost savings and will result in improved system performance in the event of a large earthquake. The Central Weather Bureau has implemented the Taiwan Strong Motion Instrumentation Program (TSMIP) to collect high-quality instrumental recordings of strong earthquake shaking.It is necessary for us to study the strong ground motion characteristics at the Ilan area of northeastern Taiwan. Further analyses using a good quality data base that includes 486 events and 4172 recordings of magnitude greater than 4.0 are required to derive the next generation attenuation of ground motion in Ilan area. In addition, Liu and Tsai (2007) used a catalog of more than 1840 shallow earthquakes with homogenized Mw magnitude ranging from 5.0 to 8.2 in 1900-2007 to estimate the seismic hazard potential in Taiwan. As a result, the PGA and PGV contour patterns of maximum ground motion show that Ilan Plain has high values of 0.2g and 80cm/sec with respect to MMI intensity VII and IX, respectively. Furthermore, from the mean ground motion and the seismic intensity rate analyses, they show that a high annul probability of MMI > VI greater than 35 percents are located at the Chianan area of western Taiwan and Ilan Plain in northeastern Taiwan. However, these results was

  9. High-frequency ground motion scaling in the Gulf of Corinth (Greece)

    NASA Astrophysics Data System (ADS)

    Evangelidis, Christos P.; D'Amico, Sebastiano; Melis, Nikolaos S.

    2014-05-01

    The evaluation of the expected peak ground motion caused by an earthquake is of great importance in seismicity and earthquake engineering studies. In the present study, weak-motion data related to small earthquakes are used, in order to extrapolate peak ground motion parameters beyond the magnitude range of the weak-motion dataset, on which they are calculated. A complete description of the seismic ground-motion characteristics in the Gulf of Corinth region in Greece is provided, with parameterization of the attenuation of seismic ground motions with distance and their variability in excitation with earthquake magnitude. We use over 1000 earthquakes recorded at the Hellenic Unified Seismic Network (HUSN) with magnitudes larger than 2.5 ML. Following a regression analysis of this large number of weak-motion data, we determine a frequency-dependent crustal quality factor, a geometrical spreading function and the absolute source scaling. In order to calibrate sufficiently the source scaling, it is necessary to use the available moment magnitude values of events from the selected dataset. The National Observatory of Athens Moment Tensor Database (NOA-MTs) is used, which includes 52 events in the range 3.3 to 5.4 MW for the time period in analysis. Complementary, we calculate moment tensor solutions with high-quality for small events not included in the NOA-MTs catalogue, using the 'Cut And Paste' technique. Results on region-specific crustal attenuation and source scaling, together with the effective duration of seismic ground motion in the region, are used to estimate the peak ground motion parameters, such as PGA, PGV, and SA at different frequencies. Using stochastic ground motion simulations, we predict the absolute level of ground shaking and compare them with strong motion data in the region. The attenuation of simulated ground motion is compared with recent global and regional ground motion prediction equations (GMPEs). The performance of the stochastic model is

  10. Characteristics of the Strong Ground Motions from the 23 October 2011 Van earthquake, Turkey

    NASA Astrophysics Data System (ADS)

    Akinci, A.; Antonioli, A.

    2012-12-01

    The recent 23 October 2011 Mw 7.1 Van Earthquake occurred at 13:41 local time in Eastern Turkey with an epicenter at 43.36oE, 38.76oN (KOERI) caused severe damage in the epicenter area. Intenseve aftershocks followed, activating the several previously unknown small scale faults around the main fault rupture. Twenty-two accelerometric stations belonging to the National Strong Ground Motion Network (operated by the Earthquake Department of the Disaster and Emergency Management Presidency, AFAD) and eleven accelerometric stations of the Iranian Strong Motion Network (ISMN) recorded the main shock. In this study a great effort has been directed towards understanding the characteristics of ground motion associated with the Van Lake seismic sequences. In this respect we study the features of the strong ground motion recordings obtained during the main shock by means of the spatial variations of the peak ground accelerations and peak ground velocities, and the spectral accelerations (5% of critical damping) together with the site amplifications. High frequency ground motion stochastic simulations are performed in the near-fault area and compared with the empirical Ground Motion Prediction Equations (GMPEs). Finally, regarding the October-November Van earthquake sequence, a static analysis of the Coulomb Failure Function variation is carried out adopting the slip distributions retrieved by USGS (Hayes, 2011).

  11. Characteristics of ground motion at permafrost sites along the Qinghai-Tibet railway

    USGS Publications Warehouse

    Wang, L.; Wu, Z.; Sun, Jielun; Liu, Xiuying; Wang, Z.

    2009-01-01

    Based on 14 typical drilling holes distributed in the permafrost areas along the Qinghai-Tibet railway, the distribution of wave velocities of soils in the permafrost regions were determined. Using results of dynamic triaxial tests, the results of dynamic triaxiality test and time histories of ground motion acceleration in this area, characteristics of ground motion response were analyzed for these permafrost sites for time histories of ground accelerations with three exceedance probabilities (63%, 10% and 2%). The influence of ground temperature on the seismic displacement, velocity, acceleration and response spectrum on the surface of permafrost were also studied. ?? 2008 Elsevier Ltd. All rights reserved.

  12. DEVELOPMENT OF DISPLAY SYSTEM OF EATTHQUAKE GROUND MOTIONS USING RELIEF MAP AND LED

    NASA Astrophysics Data System (ADS)

    Tsujihara, Osamu; Shirakase, Yuya; Nakashima, Hiroyuki; Okamoto, Terumasa

    An LED display system of earthquake ground motions is developed as a teaching material for disaster prevention. The time history of the seismic motions can be simultaneously demonstrated at many sites by illuminating computer-controlled LED embedded in the relief map. The LEDs are located at the observation sites of K-NET on the map, which is employed by NIED (National Research Institute for Earth Science and Disaster Prevention), and any earthquake motions downloaded from the website can be applied. Better educational effect and more realistic expression for the understanding of earthquake ground motions can be expected by using this system compared with by using the computer graphics. Moreover, it is helpful to understand the relation between the geological features and the ground motions since the relief map is used.

  13. Experimental Study of Ground Effect on Three-Dimensional Insect-Like Flapping Motion

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohu; Lua, Kim Boon; Chang, Rong; Lim, Tee Tai; Yeo, Khoon Seng

    2014-11-01

    This paper focuses on an experimental investigation aimed at evaluating the aerodynamics force characteristics of three-dimensional (3D) insect-like flapping motion in the vicinity of ground. The purpose is to establish whether flapping wing insects can derive aerodynamic benefit from ground effect similar to that experienced by a fixed wing aircraft. To evaluate this, force measurements were conducted in a large water tank using a 3D flapping mechanism capable of executing various insect flapping motions. Here, we focus on three types of flapping motions, namely simple harmonic flapping motion, hawkmoth-like hovering motion and fruitfly-like hovering motion, and two types of wing planforms (i.e. hawkmoth-like wing and fruitfly-like wing). Results show that hawkmoth-like wing executing simple harmonic flapping motion produces average lift to drag ratio (\\bar C\\bar L/\\bar C\\bar D) similar to that of fruitfly wing executing the same motion. In both cases, they are relatively independent of the wing distance from the ground. On the other hand, a hawkmoth wing executing hawkmoth flapping motion produces (\\bar C\\bar L/\\bar C\\bar D) characteristic different from that of fruitfly wing executing fruitfly motion. While the (\\bar C\\bar L/\\bar C\\bar D) value of the former is a function of the wing distance from the ground, the latter is minimally affected by ground effect. Unlike fixed wing aerodynamics, all the flapping wing cases considered here do not show a monotonic increase in (\\bar C\\bar L/\\bar C\\bar D) with decreasing wing distance from the ground.

  14. Ground motion following selection of SRS design basis earthquake and associated deterministic approach

    SciTech Connect

    Not Available

    1991-03-01

    This report summarizes the results of a deterministic assessment of earthquake ground motions at the Savannah River Site (SRS). The purpose of this study is to assist the Environmental Sciences Section of the Savannah River Laboratory in reevaluating the design basis earthquake (DBE) ground motion at SRS during approaches defined in Appendix A to 10 CFR Part 100. This work is in support of the Seismic Engineering Section's Seismic Qualification Program for reactor restart.

  15. A revised ground-motion and intensity interpolation scheme for shakemap

    USGS Publications Warehouse

    Worden, C.B.; Wald, D.J.; Allen, T.I.; Lin, K.; Garcia, D.; Cua, G.

    2010-01-01

    We describe a weighted-average approach for incorporating various types of data (observed peak ground motions and intensities and estimates from groundmotion prediction equations) into the ShakeMap ground motion and intensity mapping framework. This approach represents a fundamental revision of our existing ShakeMap methodology. In addition, the increased availability of near-real-time macroseismic intensity data, the development of newrelationships between intensity and peak ground motions, and new relationships to directly predict intensity from earthquake source information have facilitated the inclusion of intensity measurements directly into ShakeMap computations. Our approach allows for the combination of (1) direct observations (ground-motion measurements or reported intensities), (2) observations converted from intensity to ground motion (or vice versa), and (3) estimated ground motions and intensities from prediction equations or numerical models. Critically, each of the aforementioned data types must include an estimate of its uncertainties, including those caused by scaling the influence of observations to surrounding grid points and those associated with estimates given an unknown fault geometry. The ShakeMap ground-motion and intensity estimates are an uncertainty-weighted combination of these various data and estimates. A natural by-product of this interpolation process is an estimate of total uncertainty at each point on the map, which can be vital for comprehensive inventory loss calculations. We perform a number of tests to validate this new methodology and find that it produces a substantial improvement in the accuracy of ground-motion predictions over empirical prediction equations alone.

  16. Vertical ground motion and historical sea-level records in Dakar (Senegal)

    NASA Astrophysics Data System (ADS)

    Le Cozannet, Gonéri; Raucoules, Daniel; Wöppelmann, Guy; Garcin, Manuel; Da Sylva, Sylvestre; Meyssignac, Benoit; Gravelle, Médéric; Lavigne, Franck

    2015-08-01

    With growing concerns regarding future impacts of sea-level in major coastal cities, the most accurate information is required regarding local sea-level changes with respect to the coast. Besides global and regional sea-level changes, local coastal vertical ground motions can substantially contribute to local changes in sea-level. In some cases, such ground motions can also limit the usefulness of tide-gauge records, which are a unique source of information to evaluate global sea-level changes before the altimetry era. Using satellite synthetic aperture radar interferometry, this study aims at characterizing vertical coastal ground motion in Dakar (Senegal), where a unique century-long record in Africa has been rediscovered. Given the limited number of available images, we use a stacking procedure to compute ground motion velocities in the line of sight over 1992-2010. Despite a complex geology and a rapid population growth and development, we show that the city as a whole is unaffected by differential ground motions larger than 1 mm year-1. Only the northern part of the harbor displays subsidence patterns after 2000, probably as a consequence of land reclamation works. However, these ground motions do not affect the historical tide gauge. Our results highlight the value of the historical sea-level records of Dakar, which cover a 100 year time-span in a tropical oceanic region of Africa, where little data are available for past sea-level reconstructions.

  17. Measurements of ground motion and SSC dipole vibrations

    SciTech Connect

    Parkhomchuk, V.V.; Shiltsev, V.D.; Weaver, H.J.

    1993-06-01

    The results of seismic ground measurements at the Superconducting Super Collider (SSC) site and investigations of vibrational properties of superconducting dipoles for the SSC are presented. Spectral analysis of the data obtained in the large frequency band from 0.05 Hz to 2000 Hz is done. Resonant behavior and the dipole-to-ground transform ratio are investigated. The influence of measured vibrations on SSC operations is considered.

  18. On the unsteady motion and stability of a heaving airfoil in ground effect

    NASA Astrophysics Data System (ADS)

    Molina, Juan; Zhang, Xin; Angland, David

    2011-04-01

    This study explores the fluid mechanics and force generation capabilities of an inverted heaving airfoil placed close to a moving ground using a URANS solver with the Spalart-Allmaras turbulence model. By varying the mean ground clearance and motion frequency of the airfoil, it was possible to construct a frequency-height diagram of the various forces acting on the airfoil. The ground was found to enhance the downforce and reduce the drag with respect to freestream. The unsteady motion induces hysteresis in the forces' behaviour. At moderate ground clearance, the hysteresis increases with frequency and the airfoil loses energy to the flow, resulting in a stabilizingmotion. By analogy with a pitching motion, the airfoil stalls in close proximity to the ground. At low frequencies, the motion is unstable and could lead to stall flutter. A stall flutter analysis was undertaken. At higher frequencies, inviscid effects overcome the large separation and the motion becomes stable. Forced trailing edge vortex shedding appears at high frequencies. The shedding mechanism seems to be independent of ground proximity. However, the wake is altered at low heights as a result of an interaction between the vortices and the ground.

  19. Stochastic Modeling and Simulation of Near-Fault Ground Motions for Performance-Based Earthquake Engineering

    NASA Astrophysics Data System (ADS)

    Dabaghi, Mayssa Nabil

    A comprehensive parameterized stochastic model of near-fault ground motions in two orthogonal horizontal directions is developed. The proposed model uniquely combines several existing and new sub-models to represent major characteristics of recorded near-fault ground motions. These characteristics include near-fault effects of directivity and fling step; temporal and spectral non-stationarity; intensity, duration and frequency content characteristics; directionality of components, as well as the natural variability of motions for a given earthquake and site scenario. By fitting the model to a database of recorded near-fault ground motions with known earthquake source and site characteristics, empirical "observations" of the model parameters are obtained. These observations are used to develop predictive equations for the model parameters in terms of a small number of earthquake source and site characteristics. Functional forms for the predictive equations that are consistent with seismological theory are employed. A site-based simulation procedure that employs the proposed stochastic model and predictive equations is developed to generate synthetic near-fault ground motions at a site. The procedure is formulated in terms of information about the earthquake design scenario that is normally available to a design engineer. Not all near-fault ground motions contain a forward directivity pulse, even when the conditions for such a pulse are favorable. The proposed procedure produces pulselike and non-pulselike motions in the same proportions as they naturally occur among recorded near-fault ground motions for a given design scenario. The proposed models and simulation procedure are validated by several means. Synthetic ground motion time series with fitted parameter values are compared with the corresponding recorded motions. The proposed empirical predictive relations are compared to similar relations available in the literature. The overall simulation procedure is

  20. Effects of near-fault ground motions on the nonlinear behaviour of reinforced concrete framed buildings

    NASA Astrophysics Data System (ADS)

    Mazza, Mirko

    2015-07-01

    The design provisions of current seismic codes are generally not very accurate for assessing effects of near-fault ground motions on reinforced concrete (r.c.) spatial frames, because only far-fault ground motions are considered in the seismic codes. Strong near-fault earthquakes are characterized by long-duration (horizontal) pulses and high values of the ratio α PGA of the peak value of the vertical acceleration, PGAV, to the analogous value of the horizontal acceleration, PGAH, which can become critical for girders and columns. In this work, six- and twelve-storey r.c. spatial frames are designed according to the provisions of the Italian seismic code, considering the horizontal seismic loads acting (besides the gravity loads) alone or in combination with the vertical ones. The nonlinear seismic analysis of the test structures is performed using a step-by-step procedure based on a two-parameter implicit integration scheme and an initial stress-like iterative procedure. A lumped plasticity model based on the Haar-Kàrmàn principle is adopted to model the inelastic behaviour of the frame members. For the numerical investigation, five near-fault ground motions with high values of the acceleration ratio α PGA are considered. Moreover, following recent seismological studies, which allow the extraction of the largest (horizontal) pulse from a near-fault ground motion, five pulse-type (horizontal) ground motions are selected by comparing the original ground motion with the residual motion after the pulse has been extracted. The results of the nonlinear dynamic analysis carried out on the test structures highlighted that horizontal and vertical components of near-fault ground motions may require additional consideration in the seismic codes.

  1. Broad-band near-field ground motion simulations in 3-dimensional scattering media

    NASA Astrophysics Data System (ADS)

    Imperatori, W.; Mai, P. M.

    2013-02-01

    The heterogeneous nature of Earth's crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broad-band ground-motion calculations, either considering scattering as a semi-stochastic or purely stochastic process. In this study, we simulate broad-band (0-10 Hz) ground motions with a 3-D finite-difference wave propagation solver using several 3-D media characterized by von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its influence on the seismic wavefield at short and intermediate distances from the source in terms of ground motion parameters. We also examine scattering phenomena, related to the loss of radiation pattern and the directivity breakdown. We first simulate broad-band ground motions for a point-source characterized by a classic ω2 spectrum model. Fault finiteness is then introduced by means of a Haskell-type source model presenting both subshear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for peak ground velocity (PGV) calculations. At the same time, we find a gradual loss of the source signature in the 2-5 Hz frequency range, together with a distortion of the Mach cones in case of super-shear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggests that von Karman correlation functions with correlation length between several hundred metres and few kilometres, Hurst exponent around 0.3 and standard deviation in the 5-10 per cent range

  2. A synthetic GMPE based on deterministic simulated ground motion data obtained from dynamic rupture models

    NASA Astrophysics Data System (ADS)

    Dalguer, L. A.; Baumann, C.; Cauzzi, C.

    2013-12-01

    Empirical ground motion prediction in the very near-field and for large magnitudes is often based on extrapolation of ground motion prediction equations (GMPEs) outside the range where they are well constrained by recorded data. With empirical GMPEs it is also difficult to capture source-dominated ground motion patterns, such as the effects of velocity pulses induced by subshear and supershear rupture directivity, buried and surface-rupturing, hanging-wall and foot-wall, weak shallow layers, complex geometry faults and stress drop. A way to cope at least in part with these shortcomings is to augment the calibration datasets with synthetic ground motions. To this aim, physics-based dynamic rupture models - where the physical bases involved in the fault rupture are explicitly considered - appear to be a suitable approach to produce synthetic ground motions. In this contribution, we first perform an assessment of a database of synthetic ground motions generated by a suite of dynamic rupture simulations to verify compatibility of the peak ground amplitudes with current GMPEs. The synthetic data-set is composed by 360 earthquake scenarios with moment magnitudes in the range of 5.5-7, for three mechanisms of faulting (reverse, normal and strike-slip) and for both buried faults and surface rupturing faults. Second, we parameterise the synthetic dataset through a GMPE. For this purpose, we identify the basic functional forms by analyzing the variation of the synthetic peak ground motions and spectral ordinates as a function of different explanatory variables related to the earthquake source characteristics, in order to account for some of the source effects listed above. We argue that this study provides basic guidelines for the developments of future GMPEs including data from physics-based numerical simulations.

  3. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    NASA Astrophysics Data System (ADS)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  4. Ground-Motion Prediction Equations (GMPEs) from a global dataset: the PEERPEER NGA equations

    USGS Publications Warehouse

    Boore, David M.

    2011-01-01

    The PEER NGA ground-motion prediction equation s (GMPEs) were derived by five developer teams over several years, resulting in five sets of GMPEs. The teams used various subsets of a global database of ground motions and metadata from shallow earthquakes in tectonically active regions in the development of the equations. Since their publication, the predicted motions from these GMPEs have been compared with data from various parts of the world – data that largely were not used in the development of the GMPEs. The comparisons suggest that the NGA GMPEs are applicable globally for shallow earthquakes in tectonically active regions.

  5. A study of surface and subsurface ground motions at Calico Hills, Nevada Test Site

    USGS Publications Warehouse

    King, Kenneth W.

    1982-01-01

    A study of earthquake ground motions recorded at depth in a drill hole and at the ground surface has derived the surface to subsurface transfer functions such as might be expected at a potential nuclear waste repository in a similar setting. The site under investigation has small seismic velocity contrasts in the layers of rock between the surface and the subsurface seismometer location. The subsurface seismic motions were similar in spectral characteristics to the surface motions and were lower in amplitude across the recorded band-width by a factor of 1.5.

  6. The Response of Long-Span Bridges to Low Frequency, Near-Fault Earthquake Ground Motions

    SciTech Connect

    McCallen, David; Astaneh-Asl, A.; Larsen, S.C.; Hutchings, Larry

    2009-02-27

    Historical seismic hazard characterizations did not include earthquake ground motion waveforms at frequencies below approximately 0.2 Hz (5 seconds period). This resulted from limitations in early strong motion instrumentation and signal processing techniques, a lack of measurements in the near-field of major earthquakes and therefore no observational awareness, and a delayed understanding in the engineering community of the potential significance of these types of motions. In recent years, there is a growing recognition of the relevance of near-fault, low frequency motions, particularly for long-period structures such as large bridges. This paper describes a computationally based study of the effects of low frequency (long-period) near-fault motions on long-span bridge response. The importance of inclusion of these types of motions for long span cable supported bridges is demonstrated using actual measured broad-band, near-fault motions from large earthquakes.

  7. Designed microtremor array based actual measurement and analysis of strong ground motion at Palu city, Indonesia

    NASA Astrophysics Data System (ADS)

    Thein, Pyi Soe; Pramumijoyo, Subagyo; Brotopuspito, Kirbani Sri; Wilopo, Wahyu; Kiyono, Junji; Setianto, Agung; Putra, Rusnardi Rahmat

    2015-04-01

    In this study, we investigated the strong ground motion characteristics under Palu City, Indonesia. The shear wave velocity structures evaluated by eight microtremors measurement are the most applicable to determine the thickness of sediments and average shear wave velocity with Vs ≤ 300 m/s. Based on subsurface underground structure models identified, earthquake ground motion was estimated in the future Palu-Koro earthquake by using statistical green's function method. The seismic microzonation parameters were carried out by considering several significant controlling factors on ground response at January 23, 2005 earthquake.

  8. An estimate of maximum ground surface motion for non zero surface velocity

    NASA Astrophysics Data System (ADS)

    Pecker, Alain

    2004-09-01

    The increasing need for probability seismic hazard assessment (PSHA) of critical facilities sometimes leads to unrealistic earthquake scenarios with very high induced ground motions. From a physical standpoint these high motions cannot exist because of the limiting resistance capacity of the soil strata through which the seismic waves travel. A simple analytical model is proposed to bound the maximum ground surface acceleration that any soil deposit can transfer. This model is an extension to non zero ground surface velocity of a previously presented model. To cite this article: A. Pecker, C. R. Mecanique 332 (2004).

  9. Designed microtremor array based actual measurement and analysis of strong ground motion at Palu city, Indonesia

    SciTech Connect

    Thein, Pyi Soe; Pramumijoyo, Subagyo; Wilopo, Wahyu; Setianto, Agung; Brotopuspito, Kirbani Sri; Kiyono, Junji; Putra, Rusnardi Rahmat

    2015-04-24

    In this study, we investigated the strong ground motion characteristics under Palu City, Indonesia. The shear wave velocity structures evaluated by eight microtremors measurement are the most applicable to determine the thickness of sediments and average shear wave velocity with Vs ≤ 300 m/s. Based on subsurface underground structure models identified, earthquake ground motion was estimated in the future Palu-Koro earthquake by using statistical green’s function method. The seismic microzonation parameters were carried out by considering several significant controlling factors on ground response at January 23, 2005 earthquake.

  10. Ground Motion Characteristics Considering Magnitude Dependency and Difference Between Surface and Subsurface Rupture Earthquakes

    NASA Astrophysics Data System (ADS)

    Kagawa, T.; Irikura, K.; Some, P. G.; Miyake, H.; Sato, T.; Dan, K.; Matsu, S.

    2005-12-01

    We have studied differences in ground motion according to fault rupture types and magnitude. We found that three diffferent earthquake categories have distinct ground motion characteristics. Somerville (2003) and Kagawa et al. (2004) found that the ground motion caused by subsurface rupture in the period range around one second is larger than predicted by empirical spectral attenuation relations (Abrahamson and Silva, 1997) for all earthquakes, but ground motion from earthquakes that rupture the surface is smaller in the same period range. We expand their study to smaller earthquakes and add several recent earthquakes. WWe began by dividing the earthquakes into four categories that are a combination of two classifications, i.e. defined and undefined fault, surface and subsurface rupture earthquakes. Each category is divided into larger and smaller earthquakes than about Mw 6.5. Eventually, we classified the earthquakes into three groups: a) Surface rupture type : Ground motion is smaller than average, especially in the period range around 1 second. b) Larger subsurface rupture type : Ground motion is larger than average, especially in the period range around 1 second. c) Smaller subsurface rupture type : Ground motion is larger than average, especially in the period range around 0.1 second. Subsurface rupture earthquakes with small magnitude occur in the deep portion of the seismogenic zone. Deep and high stress asperities generate large ground motions in the short period range. They do not generate pulse like ground motions, because the asperity is too small and deep to cause forward directivity effects, and because the radiation and propagation of ground motion at short periods may be too incoherent to allow the formation of a pulse. Larger subsurface rupture earthquakes have larger asperities that may span a large part of the width of the seismogenic zone, producing coherent directivity pulses with periods of 1 second or more. Kagawa et al. (2004) pointed out

  11. Variability in wood-frame building damage using broad-band synthetic ground motions: a comparative numerical study with recorded motions

    USGS Publications Warehouse

    Pei, Shiling; van de Lindt, John W.; Hartzell, Stephen; Luco, Nicolas

    2014-01-01

    Earthquake damage to light-frame wood buildings is a major concern for North America because of the volume of this construction type. In order to estimate wood building damage using synthetic ground motions, we need to verify the ability of synthetically generated ground motions to simulate realistic damage for this structure type. Through a calibrated damage potential indicator, four different synthetic ground motion models are compared with the historically recorded ground motions at corresponding sites. We conclude that damage for sites farther from the fault (>20 km) is under-predicted on average and damage at closer sites is sometimes over-predicted.

  12. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 2, Appendices

    SciTech Connect

    Not Available

    1993-03-18

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. This document, Volume II, contains Appendices 2, 3, 5, 6, and 7 covering the following topics: Eastern North American Empirical Ground Motion Data; Examination of Variance of Seismographic Network Data; Soil Amplification and Vertical-to-Horizontal Ratios from Analysis of Strong Motion Data From Active Tectonic Regions; Revision and Calibration of Ou and Herrmann Method; Generalized Ray Procedure for Modeling Ground Motion Attenuation; Crustal Models for Velocity Regionalization; Depth Distribution Models; Development of Generic Site Effects Model; Validation and Comparison of One-Dimensional Site Response Methodologies; Plots of Amplification Factors; Assessment of Coupling Between Vertical & Horizontal Motions in Nonlinear Site Response Analysis; and Modeling of Dynamic Soil Properties.

  13. Probabilistic estimates of the seismic ground-motion hazard in western Saudi Arabia

    SciTech Connect

    Thenhaus, P.C.; Algermissen, S.T.; Perkins, D.M.; Hanson, S.L.; Diment, W.H.

    1989-01-01

    Estimates of seismic horizontal ground acceleration and velocity having a 90 percent probability of nonexceedance in 100 yr in western Saudi Arabia indicate the highest relative levels of ground motion are expected in regions neighboring the Gulf of Aqaba and North Yemen. Estimated ground motions within the Arabia Shield are relatively low; whereas the central and northern coastal plan regions are characterized by intermediate-level ground-motion values that are governed by far-field effects of earthquakes in the central Red Sea Rift. The seismic hazard estimates were derived from regional seismic source zones that are based on interpretation relating potential seismic activity to the Precambrian through Tertiary structural framework of the region.

  14. EXPERIMENTAL STUDY FOR SEISMIC SECURITY OF STEEL BRIDGE PIERS UNDER BIDIRECTIONAL GROUND MOTION EXCITATION

    NASA Astrophysics Data System (ADS)

    Dang, Ji; Aoki, Tetuhiko; Igarashi, Akira

    In this study, static cyclic loading tests, uni-directional hybrid tests, uni-directional nolinear seismic simulation using curve approximate hysteretic model developed for steel piers and bi-directional hybrid tests are conducted to clarify the seismic performance of steel bridge piers under bidirectional ground motion excitation. Nine bridge models applying 3 types of bridge pier specimens and 3 ground type conditions are designed based on the current seismic design specification. The response of these bridge models under uni- and bidirectional ground motions are obtained by pseudodanamic tests and numerical simuations. By comparing these tests and simulation results, it is found that the bridge piers could be collapsed under bi-direction ground motions, which are regarded as safe under uni-directional loading. Under the bidirectional seismic action, the capacity of steel piers degrades to averagely 84%, and their response displacement increases 20% more than the values obtained by convential uni-directional loading.

  15. Broadband Ground Motion Simulations of the 23 October 2011 Van (Eastern Turkey) Earthquake

    NASA Astrophysics Data System (ADS)

    Ameri, G.; Gallovič, F.; Askan, A.; Zahradník, J.

    2012-04-01

    On October 23, 2011, a Mw 7.1 earthquake occurred in eastern Turkey, close to the towns of Van and Erciş, causing about 600 casualties and a widespread damage. The earthquake ruptured a 60-70 km long NE-SW fault with a thrust mechanism, in agreement with the tectonic stress regime of the region. The mainshock was recorded by several stations of the Turkish and Iranian strong-motion networks providing about 20 three-component recordings within 230 km distance from the epicenter. Due to the sparse station coverage, only few strong-motion records are collected in the epicentral area (i.e., within 50 km from the earthquake fault). Thus, the details of the rupture process and the ground motion distribution in the near-fault, that are essential to investigate and assess the damage caused by the earthquake, remain largely unknown. In this study, we present preliminary results of broadband (0.1-10Hz) ground motion simulations for the Van earthquake using a hybrid integral-composite source model. The simulations are based on three fault models: (i) the USGS slip distribution calculated from teleseismic records, (ii) our slip distribution calculated from Turkish strong-motion stations, and (iii) our multiple-point source model calculated from the same data as (ii). Models (ii) and (iii), in contrast to (i), were derived independently on the assumed position of the hypocenter. We first attempt to simulate the closest strong motion records in order to calibrate some rupture model parameters that cannot be constrained from alternative studies. The sensitivity of the simulated ground motions to rupture velocity, stress drop and slip distribution over the fault is investigated. Finally, we examine the simulated ground motion distribution in the near-fault area and compare it with empirical ground motion prediction equations and with the observed damage after the earthquake.

  16. Long-period Ground Motion Simulation in the Osaka Basin during the 2011 Great Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Iwata, T.; Kubo, H.; Asano, K.; Sato, K.; Aoi, S.

    2014-12-01

    Large amplitude long-period ground motions (1-10s) with long duration were observed in the Osaka sedimentary basin during the 2011 Tohoku earthquake (Mw9.0) and its aftershock (Ibaraki-Oki, Mw7.7), which is about 600 km away from the source regions. Sato et al. (2013) analyzed strong ground motion records from the source region to the Osaka basin and showed the following characteristics. (1) In the period range of 1 to 10s, the amplitude of horizontal components of the ground motion at the site-specific period is amplified in the Osaka basin sites. The predominant period is about 7s in the bay area where the largest pSv were observed. (2) The velocity Fourier amplitude spectra with their predominant period of around 7s are observed at the bedrock sites surrounding the Osaka basin. Those characteristics were observed during both of the mainshock and the largest aftershock. Therefore, large long-period ground motions in the Osaka basin are generated by the combination of propagation-path and basin effects. They simulated ground motions due to the largest aftershock as a simple point source model using three-dimensional FDM (GMS; Aoi and Fujiwara, 1999). They used a three-dimensional velocity structure based on the Japan Integrated Velocity Structure Model (JIVSM, Koketsu et al., 2012), with the minimum effective period of the computation of 3s. Their simulation result reproduced the observation characteristics well and it validates the applicability of the JIVSM for the long period ground motion simulation. In this study, we try to simulate long-period ground motions during the mainshock. The source model we used for the simulation is based on the SMGA model obtained by Asano and Iwata (2012). We succeed to simulate long-period ground motion propagation from Kanto area to the Osaka basin fairly well. The long-period ground motion simulations with the several Osaka basin velocity structure models are done for improving the model applicability. We used strong motion

  17. Stochastic Ground Motion Simulation with Site Correction in Ilan Area, Northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    NFN, Megawati; Kuo-Liang, Wen

    2015-04-01

    Earthquake waveform is controlled by three factors - source properties, path characteristics, and local site effects. The local site effect is the important factor participate strong ground motion prediction. In this study, we used stochastic point-source method for simulating ground motion (Boore, 2005). This method has been widely used in the development of ground-motion prediction equation and in modeling the parameters that controls observed ground motion (Atkinson et al., 2009). The shallow earthquake events which recorded by Taiwan Strong Motion Instrumentation Program (TSMIP) from 1992 to 2012 are simulated with the stochastic point-source method (Boore, 1983; Boore, 2003). The earthquake records are selected with the depth from 0 to 30 km and the magnitude (Mw) from 4 to 6.5. The study area is situated in Ilan area which is located in the northeastern Taiwan. There are 70 TSMIP stations which based on the Vs30 consist of site class B, C, D, and E. Seismic parameters for stochastic method were selected based on previous studies (Sokolov et al., 2006; 2009). The crustal amplification parameter is set to the halfspace. The empirical transfer functions from 0.2 Hz to 10 Hz for each station in Ilan area will be calculated by H/H method between observed and simulated spectra (Borcheret, 1970). Ground motion prediction is calculated by selecting several target events for stochastic point-source simulating to the halfspace. The prediction of peak ground acceleration (PGA) is estimated after doing the site correction with the empirical transfer function. Finally, the simulated ground motion was compared in time domain (PGA) and frequency domain (Degree of spectrum difference, DSPD) to show the goodness of the simulation. Keywords : Stochastic point-source method, Site effect, Empirical transfer function

  18. The SCEC Broadband Platform: Open-Source Software for Strong Ground Motion Simulation and Validation

    NASA Astrophysics Data System (ADS)

    Goulet, C.; Silva, F.; Maechling, P. J.; Callaghan, S.; Jordan, T. H.

    2015-12-01

    The Southern California Earthquake Center (SCEC) Broadband Platform (BBP) is a carefully integrated collection of open-source scientific software programs that can simulate broadband (0-100Hz) ground motions for earthquakes at regional scales. The BBP scientific software modules implement kinematic rupture generation, low and high-frequency seismogram synthesis using wave propagation through 1D layered velocity structures, seismogram ground motion amplitude calculations, and goodness of fit measurements. These modules are integrated into a software system that provides user-defined, repeatable, calculation of ground motion seismograms, using multiple alternative ground motion simulation methods, and software utilities that can generate plots, charts, and maps. The BBP has been developed over the last five years in a collaborative scientific, engineering, and software development project involving geoscientists, earthquake engineers, graduate students, and SCEC scientific software developers. The BBP can run earthquake rupture and wave propagation modeling software to simulate ground motions for well-observed historical earthquakes and to quantify how well the simulated broadband seismograms match the observed seismograms. The BBP can also run simulations for hypothetical earthquakes. In this case, users input an earthquake location and magnitude description, a list of station locations, and a 1D velocity model for the region of interest, and the BBP software then calculates ground motions for the specified stations. The SCEC BBP software released in 2015 can be compiled and run on recent Linux systems with GNU compilers. It includes 5 simulation methods, 7 simulation regions covering California, Japan, and Eastern North America, the ability to compare simulation results against GMPEs, updated ground motion simulation methods, and a simplified command line user interface.

  19. Predicted Attenuation Relation and Observed Ground Motion of Gorkha Nepal Earthquake of 25 April 2015

    NASA Astrophysics Data System (ADS)

    Singh, R. P.; Ahmad, R.

    2015-12-01

    A comparison of recent observed ground motion parameters of recent Gorkha Nepal earthquake of 25 April 2015 (Mw 7.8) with the predicted ground motion parameters using exitsing attenuation relation of the Himalayan region will be presented. The recent earthquake took about 8000 lives and destroyed thousands of poor quality of buildings and the earthquake was felt by millions of people living in Nepal, China, India, Bangladesh, and Bhutan. The knowledge of ground parameters are very important in developing seismic code of seismic prone regions like Himalaya for better design of buildings. The ground parameters recorded in recent earthquake event and aftershocks are compared with attenuation relations for the Himalayan region, the predicted ground motion parameters show good correlation with the observed ground parameters. The results will be of great use to Civil engineers in updating existing building codes in the Himlayan and surrounding regions and also for the evaluation of seismic hazards. The results clearly show that the attenuation relation developed for the Himalayan region should be only used, other attenuation relations based on other regions fail to provide good estimate of observed ground motion parameters.

  20. Evaluating the compatibility of physics-based deterministic synthetic ground motion with empirical GMPE

    NASA Astrophysics Data System (ADS)

    Baumann, C.; Dalguer, L. A.

    2012-12-01

    Recent development of deterministic physics-based numerical simulations of earthquakes has contributed to substantial advances in our understanding of different aspects related to the earthquake mechanism and near source ground motion. These models have greater potential for identifying and predicting the variability of near-source ground motions dominated by the source and/or geological effects. These advances have led to increased interest in using suite of physics-based models for reliable prediction of ground motion of future earthquakes for seismic hazard assessment and risk mitigation, particularly in areas where there are few recorded ground motions. But before using synthetic ground motion, it is important to evaluate the reliability of deterministic synthetic ground motions, particularly the upper frequency limit. Current engineering practice usually use ground motion quantities estimated from empirical Ground Motion Predicting Equations (GMPE) such as peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), and spectral ordinates as input to assess building response for seismic safety of future and existing structures. Therefore it is intuitive and evident to verify the compatibility of synthetic ground motions with current empirical GMPE. In this study we attempt to do it so, to a suite of deterministic ground motion simulation generated by earthquake dynamic rupture models. We focus mainly on determining the upper frequency limit in which the synthetic ground motions are compatible to GMPE. For that purpose we have generated suite of earthquake rupture dynamic models in a layered 1D velocity structure. The simulations include 360 rupture dynamic models with moment magnitudes in the range of 5.5-7, for three styles of faulting (reverse, normal and strike slip), for both buried faults and surface rupturing faults. Normal stress and frictional strength are depth and non-depth dependent. Initial stress distribution follows

  1. Constraints provided by ground gravity observations on geocentre motions

    NASA Astrophysics Data System (ADS)

    Rogister, Y.; Mémin, A.; Rosat, S.; Hinderer, J.; Calvo, M.

    2016-06-01

    The geocentre motion is the motion of the centre of mass of the entire Earth, considered an isolated system, in a terrestrial system of reference. We first derive a formula relating the harmonic degree-1 Lagrangian variation of the gravity at a station to both the harmonic degree-1 vertical displacement of the station and the displacement of the whole Earth's centre of mass. The relationship is independent of the nature of the Earth deformation and is valid for any source of deformation. We impose no constraint on the system of reference, except that its origin must initially coincide with the centre of mass of the spherically-symmetric Earth model. Next, we consider the geocentre motion caused by surface loading. In a system of reference whose origin is the centre of mass of the solid Earth, we obtain a specific relationship between the gravity variation at the surface, the geocentre displacement and the load Love number h^' }_1, which demands the Earth's structure and rheological behaviour be known. For various networks of real or fictitious stations, we invert synthetic signals of surface gravity variations caused by atmospheric loading to retrieve the degree-1 variation of gravity. We then select 6 well distributed stations of the Global Geodynamics Project, which is a world network of superconducting gravimeters, to invert actual gravity data for the degree-1 variations and determine the geocentre displacement between the end of 2004 and the beginning of 2012, assuming it to be due to surface loading. We find annual and semi-annual displacements with amplitude 0.5 to 2.3 mm.

  2. Constraints provided by ground gravity observations on geocentre motions

    NASA Astrophysics Data System (ADS)

    Rogister, Y.; Mémin, A.; Rosat, S.; Hinderer, J.; Calvo, M.

    2016-08-01

    The geocentre motion is the motion of the centre of mass of the entire Earth, considered an isolated system, in a terrestrial system of reference. We first derive a formula relating the harmonic degree-1 Lagrangian variation of the gravity at a station to both the harmonic degree-1 vertical displacement of the station and the displacement of the whole Earth's centre of mass. The relationship is independent of the nature of the Earth deformation and is valid for any source of deformation. We impose no constraint on the system of reference, except that its origin must initially coincide with the centre of mass of the spherically symmetric Earth model. Next, we consider the geocentre motion caused by surface loading. In a system of reference whose origin is the centre of mass of the solid Earth, we obtain a specific relationship between the gravity variation at the surface, the geocentre displacement and the load Love number h^' }_1, which demands the Earth's structure and rheological behaviour be known. For various networks of real or fictitious stations, we invert synthetic signals of surface gravity variations caused by atmospheric loading to retrieve the degree-1 variation of gravity. We then select six well-distributed stations of the Global Geodynamics Project, which is a world network of superconducting gravimeters, to invert actual gravity data for the degree-1 variations and determine the geocentre displacement between the end of 2004 and the beginning of 2012, assuming it to be due to surface loading. We find annual and semi-annual displacements with amplitude 0.5-2.3 mm.

  3. Application and API for Real-time Visualization of Ground-motions and Tsunami

    NASA Astrophysics Data System (ADS)

    Aoi, S.; Kunugi, T.; Suzuki, W.; Kubo, T.; Nakamura, H.; Azuma, H.; Fujiwara, H.

    2015-12-01

    Due to the recent progress of seismograph and communication environment, real-time and continuous ground-motion observation becomes technically and economically feasible. K-NET and KiK-net, which are nationwide strong motion networks operated by NIED, cover all Japan by about 1750 stations in total. More than half of the stations transmit the ground-motion indexes and/or waveform data in every second. Traditionally, strong-motion data were recorded by event-triggering based instruments with non-continues telephone line which is connected only after an earthquake. Though the data from such networks mainly contribute to preparations for future earthquakes, huge amount of real-time data from dense network are expected to directly contribute to the mitigation of ongoing earthquake disasters through, e.g., automatic shutdown plants and helping decision-making for initial response. By generating the distribution map of these indexes and uploading them to the website, we implemented the real-time ground motion monitoring system, Kyoshin (strong-motion in Japanese) monitor. This web service (www.kyoshin.bosai.go.jp) started in 2008 and anyone can grasp the current ground motions of Japan. Though this service provides only ground-motion map in GIF format, to take full advantage of real-time strong-motion data to mitigate the ongoing disasters, digital data are important. We have developed a WebAPI to provide real-time data and related information such as ground motions (5 km-mesh) and arrival times estimated from EEW (earthquake early warning). All response data from this WebAPI are in JSON format and are easy to parse. We also developed Kyoshin monitor application for smartphone, 'Kmoni view' using the API. In this application, ground motions estimated from EEW are overlapped on the map with the observed one-second-interval indexes. The application can playback previous earthquakes for demonstration or disaster drill. In mobile environment, data traffic and battery are

  4. Tsunami simulation using submarine displacement calculated from simulation of ground motion due to seismic source model

    NASA Astrophysics Data System (ADS)

    Akiyama, S.; Kawaji, K.; Fujihara, S.

    2013-12-01

    Since fault fracturing due to an earthquake can simultaneously cause ground motion and tsunami, it is appropriate to evaluate the ground motion and the tsunami by single fault model. However, several source models are used independently in the ground motion simulation or the tsunami simulation, because of difficulty in evaluating both phenomena simultaneously. Many source models for the 2011 off the Pacific coast of Tohoku Earthquake are proposed from the inversion analyses of seismic observations or from those of tsunami observations. Most of these models show the similar features, which large amount of slip is located at the shallower part of fault area near the Japan Trench. This indicates that the ground motion and the tsunami can be evaluated by the single source model. Therefore, we examine the possibility of the tsunami prediction, using the fault model estimated from seismic observation records. In this study, we try to carry out the tsunami simulation using the displacement field of oceanic crustal movements, which is calculated from the ground motion simulation of the 2011 off the Pacific coast of Tohoku Earthquake. We use two fault models by Yoshida et al. (2011), which are based on both the teleseismic body wave and on the strong ground motion records. Although there is the common feature in those fault models, the amount of slip near the Japan trench is lager in the fault model from the strong ground motion records than in that from the teleseismic body wave. First, the large-scale ground motion simulations applying those fault models used by the voxel type finite element method are performed for the whole eastern Japan. The synthetic waveforms computed from the simulations are generally consistent with the observation records of K-NET (Kinoshita (1998)) and KiK-net stations (Aoi et al. (2000)), deployed by the National Research Institute for Earth Science and Disaster Prevention (NIED). Next, the tsunami simulations are performed by the finite

  5. Validation of attenuation models for ground motion applications in central and eastern North America

    DOE PAGESBeta

    Pasyanos, Michael E.

    2015-11-01

    Recently developed attenuation models are incorporated into standard one-dimensional (1-D) ground motion prediction equations (GMPEs), effectively making them two-dimensional (2-D) and eliminating the need to create different GMPEs for an increasing number of sub-regions. The model is tested against a data set of over 10,000 recordings from 81 earthquakes in North America. The use of attenuation models in GMPEs improves our ability to fit observed ground motions and should be incorporated into future national hazard maps. The improvement is most significant at higher frequencies and longer distances which have a greater number of wave cycles. This has implications for themore » rare high-magnitude earthquakes, which produce potentially damaging ground motions over wide areas, and drive the seismic hazards. Furthermore, the attenuation models can be created using weak ground motions, they could be developed for regions of low seismicity where empirical recordings of ground motions are uncommon and do not span the full range of magnitudes and distances.« less

  6. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 1

    SciTech Connect

    Not Available

    1993-03-18

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz.

  7. Validation of simulated earthquake ground motions based on evolution of intensity and frequency content

    USGS Publications Warehouse

    Rezaeian, Sanaz; Zhong, Peng; Hartzell, Stephen; Zareian, Farzin

    2015-01-01

    Simulated earthquake ground motions can be used in many recent engineering applications that require time series as input excitations. However, applicability and validation of simulations are subjects of debate in the seismological and engineering communities. We propose a validation methodology at the waveform level and directly based on characteristics that are expected to influence most structural and geotechnical response parameters. In particular, three time-dependent validation metrics are used to evaluate the evolving intensity, frequency, and bandwidth of a waveform. These validation metrics capture nonstationarities in intensity and frequency content of waveforms, making them ideal to address nonlinear response of structural systems. A two-component error vector is proposed to quantify the average and shape differences between these validation metrics for a simulated and recorded ground-motion pair. Because these metrics are directly related to the waveform characteristics, they provide easily interpretable feedback to seismologists for modifying their ground-motion simulation models. To further simplify the use and interpretation of these metrics for engineers, it is shown how six scalar key parameters, including duration, intensity, and predominant frequency, can be extracted from the validation metrics. The proposed validation methodology is a step forward in paving the road for utilization of simulated ground motions in engineering practice and is demonstrated using examples of recorded and simulated ground motions from the 1994 Northridge, California, earthquake.

  8. Validation of attenuation models for ground motion applications in central and eastern North America

    SciTech Connect

    Pasyanos, Michael E.

    2015-11-01

    Recently developed attenuation models are incorporated into standard one-dimensional (1-D) ground motion prediction equations (GMPEs), effectively making them two-dimensional (2-D) and eliminating the need to create different GMPEs for an increasing number of sub-regions. The model is tested against a data set of over 10,000 recordings from 81 earthquakes in North America. The use of attenuation models in GMPEs improves our ability to fit observed ground motions and should be incorporated into future national hazard maps. The improvement is most significant at higher frequencies and longer distances which have a greater number of wave cycles. This has implications for the rare high-magnitude earthquakes, which produce potentially damaging ground motions over wide areas, and drive the seismic hazards. Furthermore, the attenuation models can be created using weak ground motions, they could be developed for regions of low seismicity where empirical recordings of ground motions are uncommon and do not span the full range of magnitudes and distances.

  9. Impact of ground motion characterization on conservatism and variability in seismic risk estimates

    SciTech Connect

    Sewell, R.T.; Toro, G.R.; McGuire, R.K.

    1996-07-01

    This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonly implemented at the interface of seismic hazard and fragility assessments. In particular, implication of the common practice of using a single, composite spectral shape to characterize motions of different magnitudes is investigated. Also, the impact of parameterization of ground motion on fragility and hazard assessments is shown. Examination of these results demonstrates the following. (1) There exists significant conservatism in the review spectra (usually, spectra characteristic of western U.S. earthquakes) that have been used in conducting past seismic risk assessments and seismic margin assessments for eastern U.S. nuclear power plants. (2) There is a strong dependence of seismic fragility on earthquake magnitude when PGA is used as the ground-motion characterization. When, however, magnitude-dependent spectra are anchored to a common measure of elastic spectral acceleration averaged over the appropriate frequency range, seismic fragility shows no important nor consistent dependence on either magnitude or strong-motion duration. Use of inelastic spectral acceleration (at the proper frequency) as the ground spectrum anchor demonstrates a very similar result. This study concludes that a single, composite-magnitude spectrum can generally be used to characterize ground motion for fragility assessment without introducing significant bias or uncertainty in seismic risk estimates.

  10. A Study of Site Effect on Strong Ground Motion Characteristics in Ilan, Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, K.; Taiwan Earthquake Research Center

    2010-12-01

    An evaluation of seismic hazards requires an estimate of the expected ground motion at the site of interest. The most common means of estimating this ground motion in engineering practice is the use of an attenuation relation. Numerous attenuation relationships have been developed over the years by different seismologists and engineers, each using different data sets and assumptions regarding the most appropriate functional form. A number of developments have arisen recently to suggest that a new generation of attenuation relationships is warranted. Site effects play a very important role in characterizing seismic motions because they may strongly amplify seismic motions at the last moment just before reaching the surface of the ground. Examination of the residuals for sites with different soil categories is a useful method for sets of records in which site information is not complete, and hence cannot be included explicitly within the equation. We derive the spectra acceleration of periods 0.1,0.2,1.0,2.0 and 3.0 sec according to the Next Generation Attenuation of Ground Motions (NGA) Project which were developed by Pacific Earthquake Engineering Research Center. From the site residuals for SA data, we further to obtain the site effect factor of the above periods in Taiwan area. In addition, we estimate the seismic hazard potential in Taiwan in the form of ShakeMap. In this study, the site response factor is incorporated in the present ground motion prediction models. Such prediction models will result in more realistic peak ground motion estimates for assessment of seismic hazard potential. These results provide an important database for the site evaluation of critical facilities in those relatively high earthquake hazard potential regions and will be helpful for the plan of land-using.

  11. Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest

    USGS Publications Warehouse

    Heaton, T.H.; Hartzell, S.H.

    1989-01-01

    Strong ground motions are estimated for the Pacific Northwest assuming that large shallow earthquakes, similar to those experienced in southern Chile, southwestern Japan, and Colombia, may also occur on the Cascadia subduction zone. Fifty-six strong motion recordings for twenty-five subduction earthquakes of Ms???7.0 are used to estimate the response spectra that may result from earthquakes Mw<81/4. Large variations in observed ground motion levels are noted for a given site distance and earthquake magnitude. When compared with motions that have been observed in the western United States, large subduction zone earthquakes produce relatively large ground motions at surprisingly large distances. An earthquake similar to the 22 May 1960 Chilean earthquake (Mw 9.5) is the largest event that is considered to be plausible for the Cascadia subduction zone. This event has a moment which is two orders of magnitude larger than the largest earthquake for which we have strong motion records. The empirical Green's function technique is used to synthesize strong ground motions for such giant earthquakes. Observed teleseismic P-waveforms from giant earthquakes are also modeled using the empirical Green's function technique in order to constrain model parameters. The teleseismic modeling in the period range of 1.0 to 50 sec strongly suggests that fewer Green's functions should be randomly summed than is required to match the long-period moments of giant earthquakes. It appears that a large portion of the moment associated with giant earthquakes occurs at very long periods that are outside the frequency band of interest for strong ground motions. Nevertheless, the occurrence of a giant earthquake in the Pacific Northwest may produce quite strong shaking over a very large region. ?? 1989 Birkha??user Verlag.

  12. Multi-component ground motion response spectra for coupled horizontal, vertical, angular accelerations, and tilt

    USGS Publications Warehouse

    Kalkan, E.; Graizer, V.

    2007-01-01

    Rotational and vertical components of ground motion are almost always ignored in design or in the assessment of structures despite the fact that vertical motion can be twice as much as the horizontal motion and may exceed 2g level, and rotational excitation may reach few degrees in the proximity of fault rupture. Coupling of different components of ground excitation may significantly amplify the seismic demand by introducing additional lateral forces and enhanced P-?? effects. In this paper, a governing equation of motion is postulated to compute the response of a SDOF oscillator under a multi-component excitation. The expanded equation includes secondary P-?? components associated with the combined impacts of tilt and vertical excitations in addition to the inertial forcing terms due to the angular and translational accelerations. The elastic and inelastic spectral ordinates traditionally generated considering the uniaxial input motion are compared at the end with the multi-component response spectra of coupled horizontal, vertical and tilting motions. The proposed multi-component response spectrum reflects kinematic characteristics of the ground motion that are not identifiable by the conventional spectrum itself, at least for the near-fault region where high intensity vertical shaking and rotational excitation are likely to occur.

  13. Ground-motion modeling of the 1906 San Francisco Earthquake, part II: Ground-motion estimates for the 1906 earthquake and scenario events

    USGS Publications Warehouse

    Aagaard, B.T.; Brocher, T.M.; Dolenc, D.; Dreger, D.; Graves, R.W.; Harmsen, S.; Hartzell, S.; Larsen, S.; McCandless, K.; Nilsson, S.; Petersson, N.A.; Rodgers, A.; Sjogreen, B.; Zoback, M.L.

    2008-01-01

    We estimate the ground motions produce by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

  14. Ground motion observations of the South Napa earthquake (M6.0 August 24, 2014)

    NASA Astrophysics Data System (ADS)

    Baltay, A.

    2014-12-01

    The South Napa earthquake generated peak ground motions in excess of 50%g and 50 cm/s in Napa Valley and also along strike to the south, and was recorded at 17 stations within 20 km rupture distance (Rrup) of the finite fault plane, 115 stations within 50 km, and 246 within 100 km. We compare the densely recorded ground motions to existing ground motion prediction equations (GMPEs) to understand both the spatial distribution of ground-motion amplitudes and also the relative excitation and attenuation terms from the earthquake. Using the ground-motion data as reported by ShakeMap, we examine the peak ground acceleration (PGA) and velocity, as well as the pseudo-spectral acceleration (PSA) at 0.3, 1.0 and 3.0 seconds, adjusted empirically to a single site condition of 760 m/s. Overall, the ground motions on the north-south components are larger than those on the east-west, consistent with both the generally north-south strike of the fault and the rupture directivity. At the higher frequencies (PGA and PSA of 0.3 s), the close data are very consistent with the GMPEs, implying a median stress drop near 5 MPa. For the longer period data, the GMPEs underpredict the data at close stations. At all frequencies, the distance attenuation seems to be stronger than the GMPEs would predict, which could either be a station coverage bias, given that most of the stations are to the south of the epicenter, or may indicate that the attenuation structure in the Napa and delta region is stronger than the average attenuation in California, on which the GMPEs were built. The spatial plot of the ground motion residuals is positive to the north, in both Napa and Sonoma Valley, consistent with both the directivity and basin effect. More interestingly, perhaps, is that there is strong ground motion to the south, as well, in the along-strike direction, particularly for PSA at 1.0s. These strongly positive residuals align along an older, Quaternary fault structure associated with the Franklin

  15. Effects of 3D random correlated velocity perturbations on predicted ground motions

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Frankel, A.

    2010-01-01

    Three-dimensional, finite-difference simulations of a realistic finite-fault rupture on the southern Hayward fault are used to evaluate the effects of random, correlated velocity perturbations on predicted ground motions. Velocity perturbations are added to a three-dimensional (3D) regional seismic velocity model of the San Francisco Bay Area using a 3D von Karman random medium. Velocity correlation lengths of 5 and 10 km and standard deviations in the velocity of 5% and 10% are considered. The results show that significant deviations in predicted ground velocities are seen in the calculated frequency range (≤1 Hz) for standard deviations in velocity of 5% to 10%. These results have implications for the practical limits on the accuracy of scenario ground-motion calculations and on retrieval of source parameters using higher-frequency, strong-motion data.

  16. Analytical approach to calculation of response spectra from seismological models of ground motion

    USGS Publications Warehouse

    Safak, Erdal

    1988-01-01

    An analytical approach to calculate response spectra from seismological models of ground motion is presented. Seismological models have three major advantages over empirical models: (1) they help in an understanding of the physics of earthquake mechanisms, (2) they can be used to predict ground motions for future earthquakes and (3) they can be extrapolated to cases where there are no data available. As shown with this study, these models also present a convenient form for the calculation of response spectra, by using the methods of random vibration theory, for a given magnitude and site conditions. The first part of the paper reviews the past models for ground motion description, and introduces the available seismological models. Then, the random vibration equations for the spectral response are presented. The nonstationarity, spectral bandwidth and the correlation of the peaks are considered in the calculation of the peak response.

  17. Vibrating barrier: a novel device for the passive control of structures under ground motion

    PubMed Central

    Cacciola, P.; Tombari, A.

    2015-01-01

    A novel device, called vibrating barrier (ViBa), that aims to reduce the vibrations of adjacent structures subjected to ground motion waves is proposed. The ViBa is a structure buried in the soil and detached from surrounding buildings that is able to absorb a significant portion of the dynamic energy arising from the ground motion. The working principle exploits the dynamic interaction among vibrating structures due to the propagation of waves through the soil, namely the structure–soil–structure interaction. The underlying theoretical aspects of the novel control strategy are scrutinized along with its numerical modelling. Closed-form solutions are also derived to design the ViBa in the case of harmonic excitation. Numerical and experimental analyses are performed in order to investigate the efficiency of the device in mitigating the effects of ground motion waves on the structural response. A significant reduction in the maximum structural acceleration of 87% has been achieved experimentally. PMID:26345731

  18. Stochastic point-source modeling of ground motions in the Cascadia region

    USGS Publications Warehouse

    Atkinson, G.M.; Boore, D.M.

    1997-01-01

    A stochastic model is used to develop preliminary ground motion relations for the Cascadia region for rock sites. The model parameters are derived from empirical analyses of seismographic data from the Cascadia region. The model is based on a Brune point-source characterized by a stress parameter of 50 bars. The model predictions are compared to ground-motion data from the Cascadia region and to data from large earthquakes in other subduction zones. The point-source simulations match the observations from moderate events (M 100 km). The discrepancy at large magnitudes suggests further work on modeling finite-fault effects and regional attenuation is warranted. In the meantime, the preliminary equations are satisfactory for predicting motions from events of M < 7 and provide conservative estimates of motions from larger events at distances less than 100 km.

  19. Newtonian noise and ambient ground motion for gravitational wave detectors

    NASA Astrophysics Data System (ADS)

    Beker, M. G.; van den Brand, J. F. J.; Hennes, E.; Rabeling, D. S.

    2012-06-01

    Fluctuations of the local gravitational field as a result of seismic and atmospheric displacements will limit the sensitivity of ground based gravitational wave detectors at frequencies below 10 Hz. We discuss the implications of Newtonian noise for future third generation gravitational wave detectors. The relevant seismic wave fields are predominately of human origin and are dependent on local infrastructure and population density. Seismic studies presented here show that considerable seismic noise reduction is possible compared to current detector locations. A realistic seismic amplitude spectral density of a suitably quiet site should not exceed 0.5 nm/(Hz/f)2 above 1 Hz. Newtonian noise models have been developed both analytically and by finite element analysis. These show that the contribution to Newtonian noise from surface waves due to distance sources significantly reduces with depth. Seismic displacements from local sources and body waves then become the dominant contributors to the Newtonian fluctuations.

  20. Bounding Ground Motions for Hayward Fault Scenario Earthquakes Using Suites of Stochastic Rupture Models

    NASA Astrophysics Data System (ADS)

    Rodgers, A. J.; Xie, X.; Petersson, A.

    2007-12-01

    The next major earthquake in the San Francisco Bay area is likely to occur on the Hayward-Rodgers Creek Fault system. Attention on the southern Hayward section is appropriate given the upcoming 140th anniversary of the 1868 M 7 rupture coinciding with the estimated recurrence interval. This presentation will describe ground motion simulations for large (M > 6.5) earthquakes on the Hayward Fault using a recently developed elastic finite difference code and high-performance computers at Lawrence Livermore National Laboratory. Our code easily reads the recent USGS 3D seismic velocity model of the Bay Area developed in 2005 and used for simulations of the 1906 San Francisco and 1989 Loma Prieta earthquakes. Previous work has shown that the USGS model performs very well when used to model intermediate period (4-33 seconds) ground motions from moderate (M ~ 4-5) earthquakes (Rodgers et al., 2008). Ground motions for large earthquakes are strongly controlled by the hypocenter location, spatial distribution of slip, rise time and directivity effects. These are factors that are impossible to predict in advance of a large earthquake and lead to large epistemic uncertainties in ground motion estimates for scenario earthquakes. To bound this uncertainty, we are performing suites of simulations of scenario events on the Hayward Fault using stochastic rupture models following the method of Liu et al. (Bull. Seism. Soc. Am., 96, 2118-2130, 2006). These rupture models have spatially variable slip, rupture velocity, rise time and rake constrained by characterization of inferred finite fault ruptures and expert opinion. Computed ground motions show variability due to the variability in rupture models and can be used to estimate the average and spread of ground motion measures at any particular site. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No.W-7405-Eng-48. This is

  1. Ground-Motion Simulations of Scenario Earthquakes on the Hayward Fault

    SciTech Connect

    Aagaard, B; Graves, R; Larsen, S; Ma, S; Rodgers, A; Ponce, D; Schwartz, D; Simpson, R; Graymer, R

    2009-03-09

    We compute ground motions in the San Francisco Bay area for 35 Mw 6.7-7.2 scenario earthquake ruptures involving the Hayward fault. The modeled scenarios vary in rupture length, hypocenter, slip distribution, rupture speed, and rise time. This collaborative effort involves five modeling groups, using different wave propagation codes and domains of various sizes and resolutions, computing long-period (T > 1-2 s) or broadband (T > 0.1 s) synthetic ground motions for overlapping subsets of the suite of scenarios. The simulations incorporate 3-D geologic structure and illustrate the dramatic increase in intensity of shaking for Mw 7.05 ruptures of the entire Hayward fault compared with Mw 6.76 ruptures of the southern two-thirds of the fault. The area subjected to shaking stronger than MMI VII increases from about 10% of the San Francisco Bay urban area in the Mw 6.76 events to more than 40% of the urban area for the Mw 7.05 events. Similarly, combined rupture of the Hayward and Rodgers Creek faults in a Mw 7.2 event extends shaking stronger than MMI VII to nearly 50% of the urban area. For a given rupture length, the synthetic ground motions exhibit the greatest sensitivity to the slip distribution and location inside or near the edge of sedimentary basins. The hypocenter also exerts a strong influence on the amplitude of the shaking due to rupture directivity. The synthetic waveforms exhibit a weaker sensitivity to the rupture speed and are relatively insensitive to the rise time. The ground motions from the simulations are generally consistent with Next Generation Attenuation ground-motion prediction models but contain long-period effects, such as rupture directivity and amplification in shallow sedimentary basins that are not fully captured by the ground-motion prediction models.

  2. Hazard assessment of long-period ground motions for the Nankai Trough earthquakes

    NASA Astrophysics Data System (ADS)

    Maeda, T.; Morikawa, N.; Aoi, S.; Fujiwara, H.

    2013-12-01

    We evaluate a seismic hazard for long-period ground motions associated with the Nankai Trough earthquakes (M8~9) in southwest Japan. Large interplate earthquakes occurring around the Nankai Trough have caused serious damages due to strong ground motions and tsunami; most recent events were in 1944 and 1946. Such large interplate earthquake potentially causes damages to high-rise and large-scale structures due to long-period ground motions (e.g., 1985 Michoacan earthquake in Mexico, 2003 Tokachi-oki earthquake in Japan). The long-period ground motions are amplified particularly on basins. Because major cities along the Nankai Trough have developed on alluvial plains, it is therefore important to evaluate long-period ground motions as well as strong motions and tsunami for the anticipated Nankai Trough earthquakes. The long-period ground motions are evaluated by the finite difference method (FDM) using 'characterized source models' and the 3-D underground structure model. The 'characterized source model' refers to a source model including the source parameters necessary for reproducing the strong ground motions. The parameters are determined based on a 'recipe' for predicting strong ground motion (Earthquake Research Committee (ERC), 2009). We construct various source models (~100 scenarios) giving the various case of source parameters such as source region, asperity configuration, and hypocenter location. Each source region is determined by 'the long-term evaluation of earthquakes in the Nankai Trough' published by ERC. The asperity configuration and hypocenter location control the rupture directivity effects. These parameters are important because our preliminary simulations are strongly affected by the rupture directivity. We apply the system called GMS (Ground Motion Simulator) for simulating the seismic wave propagation based on 3-D FDM scheme using discontinuous grids (Aoi and Fujiwara, 1999) to our study. The grid spacing for the shallow region is 200 m and

  3. Evaluating Late Pleistocene and Holocene Rupture, Seismic Hazards and Ground Motion in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Schmauder, Gretchen Cathleen

    Chapter two in this study is a reevaluation of active faulting across the Tahoe basin a combination of airborne LiDAR (Light Detection and Ranging) imagery, high-resolution seismic CHIRP profiles, multibeam bathymetric mapping, and field mapping. The combined lateral and vertical resolution has allowed a straight forward identification of the landward extension of fault scarps associated with the three major active fault zones in the Tahoe basin: the West Tahoe-Dollar Point fault, Stateline-North Tahoe fault, and Incline Village fault. Chapter 3 in this study evaluates seismic hazard within the basin as a result of earthquake rupture on the faults identified in the first part of this study. The Ground motions modeled using Nevada ShakeZoning, a physics-based method incorporating geotechnical information and basin shape determined from geophysical methods, peak ground velocity (PGV) maps considerably different (and more accurate) than those obtained from ShakeMap, a standard USGS tool for ground motion estimation. Although ShakeMap over-predicts ground shaking outside the Lake Tahoe basin, it substantially under-predicts ground motions within the basin. eWave propagation models indicate strong, sustained shaking in the basin, threatening several communities. Annual rates of exceedance maps show the higher rates of exceedance of key ground-motion levels strongly correlate with the basin shape. The purpose of this study is to provide both better ground motion estimates and more useful shaking maps to local communities. Chapter 4 begins the validation process of the models developed as part of Chapter 3 to events recorded at Nevada Seismological Laboratory seismic stations.

  4. Ground motion issues for seismic analysis of tall buildings: A status report

    USGS Publications Warehouse

    Bozorgnia, Y.; Campbell, K.W.; Luco, N.; Moehle, J.P.; Naeim, F.; Somerville, P.; Yang, T.Y.

    2007-01-01

    The Pacific Earthquake Engineering Research Center (PEER) is coordinating a major multidisciplinary programme, the Tall Buildings Initiative (TBI), to address critical technical issues related to the design and analysis of new tall buildings located in coastal California. The authors of this paper, listed alphabetically, are involved in various research studies related to ground motion modelling, selection, modification and simulation for analysis of tall buildings. This paper summarizes the scope and progress of ongoing activities related to ground motion issues for response history analysis of tall buildings.

  5. Proceedings of Workshop XVI; The dynamic characteristics of faulting inferred from recordings of strong ground motion

    USGS Publications Warehouse

    1982-01-01

    The strong ground motions radiated by earthquake faulting are controlled by the dynamic characteristics of the faulting process. Although this assertion seems self-evident, seismologists have only recently begun to derive and test quantitative relations between common measures of strong ground motion and the dynamic characteristics of faulting. Interest in this problem has increased dramatically in past several years, however, resulting in a number of important advances. The research presented in this workshop is a significant part of this scientific development. Watching this development occur through the work of many scientists is exciting; to be able to gather a number of these scientists together in one workshop is a remarkable opportunity.

  6. Ranking of several ground-motion models for seismic hazard analysis in Iran

    NASA Astrophysics Data System (ADS)

    Ghasemi, H.; Zare, M.; Fukushima, Y.

    2008-09-01

    In this study, six attenuation relationships are classified with respect to the ranking scheme proposed by Scherbaum et al (2004 Bull. Seismol. Soc. Am. 94 1-22). First, the strong motions recorded during the 2002 Avaj, 2003 Bam, 2004 Kojour and 2006 Silakhor earthquakes are consistently processed. Then the normalized residual sets are determined for each selected ground-motion model, considering the strong-motion records chosen. The main advantage of these records is that corresponding information about the causative fault plane has been well studied for the selected events. Such information is used to estimate several control parameters which are essential inputs for attenuation relations. The selected relations (Zare et al (1999 Soil Dyn. Earthq. Eng. 18 101-23) Fukushima et al (2003 J. Earthq. Eng. 7 573-98) Sinaeian (2006 PhD Thesis International Institute of Earthquake Engineering and Seismology, Tehran, Iran); Boore and Atkinson (2007 PEER, Report 2007/01); Campbell and Bozorgnia (2007 PEER, Report 2007/02); and Chiou and Youngs (2006 PEER Interim Report for USGS Review)) have been deemed suitable for predicting peak ground-motion amplitudes in the Iranian plateau. Several graphical techniques and goodness-of-fit measures are also applied for statistical distribution analysis of the normalized residual sets. Such analysis reveals ground-motion models, developed using Iranian strong-motion records as the most appropriate ones in the Iranian context. The results of the present study are applicable in seismic hazard assessment projects in Iran.

  7. Addressing earthquake strong ground motion issues at the Idaho National Engineering Laboratory

    SciTech Connect

    Wong, I.G. ); Silva, W.J.; Stark, C.L. ); Jackson, S.; Smith, R.P. )

    1991-01-01

    In the course of reassessing seismic hazards at the Idaho National Engineering Laboratory (INEL), several key issues have been raised concerning the effects of the earthquake source and site geology on potential strong ground motions that might be generated by a large earthquake. The design earthquake for the INEL is an approximate moment magnitude (M{sub w}) 7 event that may occur on the southern portion of the Lemhi fault, a Basin and Range normal fault that is located on the northwestern boundary of the eastern Snake River Plain and the INEL, within 10 to 27km of several major facilities. Because the locations of these facilities place them at close distances to a large earthquake and generally along strike of the causative fault, the effects of source rupture dynamics (e.g., directivity) could be critical in enhancing potential ground shaking at the INEL. An additional source issue that has been addressed is the value of stress drop to use in ground motions predictions. In terms of site geology, it has been questioned whether the interbedded volcanic stratigraphy beneath the ESRP and the INEL attenuates ground motions to a greater degree than a typical rock site in the western US. These three issues have been investigated employing a stochastic ground motion methodology which incorporates the Band-Limited-White-Noise source model for both a point source and finite fault, random vibration theory and an equivalent linear approach to model soil response.

  8. Addressing earthquake strong ground motion issues at the Idaho National Engineering Laboratory

    SciTech Connect

    Wong, I.G.; Silva, W.J.; Stark, C.L.; Jackson, S.; Smith, R.P.

    1991-12-31

    In the course of reassessing seismic hazards at the Idaho National Engineering Laboratory (INEL), several key issues have been raised concerning the effects of the earthquake source and site geology on potential strong ground motions that might be generated by a large earthquake. The design earthquake for the INEL is an approximate moment magnitude (M{sub w}) 7 event that may occur on the southern portion of the Lemhi fault, a Basin and Range normal fault that is located on the northwestern boundary of the eastern Snake River Plain and the INEL, within 10 to 27km of several major facilities. Because the locations of these facilities place them at close distances to a large earthquake and generally along strike of the causative fault, the effects of source rupture dynamics (e.g., directivity) could be critical in enhancing potential ground shaking at the INEL. An additional source issue that has been addressed is the value of stress drop to use in ground motions predictions. In terms of site geology, it has been questioned whether the interbedded volcanic stratigraphy beneath the ESRP and the INEL attenuates ground motions to a greater degree than a typical rock site in the western US. These three issues have been investigated employing a stochastic ground motion methodology which incorporates the Band-Limited-White-Noise source model for both a point source and finite fault, random vibration theory and an equivalent linear approach to model soil response.

  9. Postures and Motions Library Development for Verification of Ground Crew Human Factors Requirements

    NASA Technical Reports Server (NTRS)

    Stambolian, Damon; Henderson, Gena; Jackson, Mariea Dunn; Dischinger, Charles

    2013-01-01

    Spacecraft and launch vehicle ground processing activities require a variety of unique human activities. These activities are being documented in a primitive motion capture library. The library will be used by human factors engineering analysts to infuse real to life human activities into the CAD models to verify ground systems human factors requirements. As the primitive models are being developed for the library, the project has selected several current human factors issues to be addressed for the Space Launch System (SLS) and Orion launch systems. This paper explains how the motion capture of unique ground systems activities is being used to verify the human factors engineering requirements for ground systems used to process the SLS and Orion vehicles, and how the primitive models will be applied to future spacecraft and launch vehicle processing.

  10. Postures and Motions Library Development for Verification of Ground Crew Human Systems Integration Requirements

    NASA Technical Reports Server (NTRS)

    Jackson, Mariea Dunn; Dischinger, Charles; Stambolian, Damon; Henderson, Gena

    2012-01-01

    Spacecraft and launch vehicle ground processing activities require a variety of unique human activities. These activities are being documented in a Primitive motion capture library. The Library will be used by the human factors engineering in the future to infuse real to life human activities into the CAD models to verify ground systems human factors requirements. As the Primitive models are being developed for the library the project has selected several current human factors issues to be addressed for the SLS and Orion launch systems. This paper explains how the Motion Capture of unique ground systems activities are being used to verify the human factors analysis requirements for ground system used to process the STS and Orion vehicles, and how the primitive models will be applied to future spacecraft and launch vehicle processing.

  11. SEISMIC PERFORMANCE OF RC BRIDGE COLUMNS UNDER VARYING AXIAL FORCE DUE TO NEAR-FIELD VERTICAL GROUND MOTIONS

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Hiroshi; Kumagai, Yuji; Kawashima, Kazuhiko

    Recently, high acceleration and high frequency near-field vertical ground motions were recorded at several sites. The extreme vertical ground motions can induce high frequency varying axial force which develop even tensile force in reinforced concrete bridge columns. Cyclic loading experiments of RC columns were conducted to clarify the seismic performance of RC bridge columns under near-field vertical ground motions. It is shown that core concrete is crushed extensively due to varying axial force after longitudinal bars buckle.

  12. SSI effects on ground motion at Lotung LSST Site

    SciTech Connect

    Borja, R.I.; Montans, F.J.; Lin, C.H.; Chao, H.Y.

    1999-09-01

    A 3D finite-element model is developed to study soil-structure interaction (SSI) effects at a Large-Scale Seismic Test (LSST) site in Lotung, Taiwan, during the earthquake of May 20, 1986. Analyses are carried out by direct method incorporating a 1/4-scale nuclear plant containment structure. The containment structure is modeled as a linearly elastic material, while the subsoil is modeled as an elastoplastic continuum material that deforms plastically according to a bounding surface plasticity theory with a vanishing elastic region. Eigenvalue analyses are performed to see how the presence of the structure affects the fundamental frequencies and modes of vibration of the system in the limit of elastic response. SSI effects are shown to be partly responsible for the reduced peak north-south ground surface acceleration recorded by a downhole array near the containment structure. Eigenvalue studies suggest that the local effect of the containment structure is to generate rocking and torsional vibration modes, in addition to the usual lateral and vertical modes. However, results of time domain studies indicate that the former modes (rocking and torsional) were not triggered by the 1986 earthquake.

  13. Revisions to some parameters used in stochastic-method simulations of ground motion

    USGS Publications Warehouse

    Boore, David; Thompson, Eric M.

    2015-01-01

    The stochastic method of ground‐motion simulation specifies the amplitude spectrum as a function of magnitude (M) and distance (R). The manner in which the amplitude spectrum varies with M and R depends on physical‐based parameters that are often constrained by recorded motions for a particular region (e.g., stress parameter, geometrical spreading, quality factor, and crustal amplifications), which we refer to as the seismological model. The remaining ingredient for the stochastic method is the ground‐motion duration. Although the duration obviously affects the character of the ground motion in the time domain, it also significantly affects the response of a single‐degree‐of‐freedom oscillator. Recently published updates to the stochastic method include a new generalized double‐corner‐frequency source model, a new finite‐fault correction, a new parameterization of duration, and a new duration model for active crustal regions. In this article, we augment these updates with a new crustal amplification model and a new duration model for stable continental regions. Random‐vibration theory (RVT) provides a computationally efficient method to compute the peak oscillator response directly from the ground‐motion amplitude spectrum and duration. Because the correction factor used to account for the nonstationarity of the ground motion depends on the ground‐motion amplitude spectrum and duration, we also present new RVT correction factors for both active and stable regions.

  14. A Hybrid Ground-Motion Prediction Equation for Earthquakes in Western Alberta

    NASA Astrophysics Data System (ADS)

    Spriggs, N.; Yenier, E.; Law, A.; Moores, A. O.

    2015-12-01

    Estimation of ground-motion amplitudes that may be produced by future earthquakes constitutes the foundation of seismic hazard assessment and earthquake-resistant structural design. This is typically done by using a prediction equation that quantifies amplitudes as a function of key seismological variables such as magnitude, distance and site condition. In this study, we develop a hybrid empirical prediction equation for earthquakes in western Alberta, where evaluation of seismic hazard associated with induced seismicity is of particular interest. We use peak ground motions and response spectra from recorded seismic events to model the regional source and attenuation attributes. The available empirical data is limited in the magnitude range of engineering interest (M>4). Therefore, we combine empirical data with a simulation-based model in order to obtain seismologically informed predictions for moderate-to-large magnitude events. The methodology is two-fold. First, we investigate the shape of geometrical spreading in Alberta. We supplement the seismic data with ground motions obtained from mining/quarry blasts, in order to gain insights into the regional attenuation over a wide distance range. A comparison of ground-motion amplitudes for earthquakes and mining/quarry blasts show that both event types decay at similar rates with distance and demonstrate a significant Moho-bounce effect. In the second stage, we calibrate the source and attenuation parameters of a simulation-based prediction equation to match the available amplitude data from seismic events. We model the geometrical spreading using a trilinear function with attenuation rates obtained from the first stage, and calculate coefficients of anelastic attenuation and site amplification via regression analysis. This provides a hybrid ground-motion prediction equation that is calibrated for observed motions in western Alberta and is applicable to moderate-to-large magnitude events.

  15. Estimation of seismic ground motions using deterministic approach for major cities of Gujarat

    NASA Astrophysics Data System (ADS)

    Shukla, J.; Choudhury, D.

    2012-06-01

    A deterministic seismic hazard analysis has been carried out for various sites of the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat region in India to compute the seismic hazard exceeding a certain level in terms of peak ground acceleration (PGA) and to estimate maximum possible PGA at each site at bed rock level. The seismic sources in Gujarat are very uncertain and recurrence intervals of regional large earthquakes are not well defined. Because the instrumental records of India specifically in the Gujarat region are far from being satisfactory for modeling the seismic hazard using the probabilistic approach, an attempt has been made in this study to accomplish it through the deterministic approach. In this regard, all small and large faults of the Gujarat region were evaluated to obtain major fault systems. The empirical relations suggested by earlier researchers for the estimation of maximum magnitude of earthquake motion with various properties of faults like length, surface area, slip rate, etc. have been applied to those faults to obtain the maximum earthquake magnitude. For the analysis, seven different ground motion attenuation relations (GMARs) of strong ground motion have been utilized to calculate the maximum horizontal ground accelerations for each major city of Gujarat. Epistemic uncertainties in the hazard computations are accounted for within a logic-tree framework by considering the controlling parameters like b-value, maximum magnitude and ground motion attenuation relations (GMARs). The corresponding deterministic spectra have been prepared for each major city for the 50th and 84th percentiles of ground motion occurrence. These deterministic spectra are further compared with the specified spectra of Indian design code IS:1893-Part I (2002) to validate them for further practical use. Close examination of the developed spectra reveals that the expected ground motion values become high for the Kachchh region i.e. Bhuj

  16. Characteristics of Ground Motions from Large-Scale Dynamic Rupture Simulations

    NASA Astrophysics Data System (ADS)

    Shi, Z.; Day, S. M.

    2012-12-01

    We investigate the characteristics of ground motions generated using an all-physics-based deterministic approach. The rupture events are simulated as dynamic ruptures along rough faults using large-scale three-dimensional models. The fault roughness assumed in our study follows self-similar fractal distribution with the roughness wavelength scales spanning three orders of magnitude from ~10^2 m to ~10^5 m. Frictional sliding on the fault is governed by a rate- and-state friction with strongly rate-weakening property and the inelastic yielding of the off-fault bulk material is subject to Drucker-Prager viscoplasticity. Our simulation results show that the fault roughness promotes the development of self-healing rupture pulses and causes loss of rupture coherence. The resulting rupture irregularity lead to ground motions of considerable complexity. Ground accelerations that show extensive high-frequency oscillations exhibit a rich variety of phases and near-flat power spectra between a few tenths of one Hz to slightly less than 10 Hz. The patterns of fault-parallel, fault-normal, vertical and geometric-mean PGAs all show considerable level of variability that appears to be quantitatively similar to that found in earthquake strong motion records. We also computed the orientation-independent RotD50 response spectra of the ground accelerations for representative periods from 0.1 to 3.0 seconds. Compared to the Ground Motion Prediction Equations for the Next Generation Attenuation project (Power et al., 2008), these RotD50 response spectra are highly consistent with those empirical estimates, within the epistemic uncertainty, giving credence to the usefulness of our approach. Our study will contribute to the better understanding of the theoretical aspects of ground motion and hopefully provide useful guidance for the future development of the seismic risk analysis in practice.

  17. Calculation of broadband time histories of ground motion: Comparison of methods and validation using strong-ground motion from the 1994 Northridge earthquake

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Frankel, A.; Larsen, S.

    1999-01-01

    This article compares techniques for calculating broadband time histories of ground motion in the near field of a finite fault by comparing synthetics with the strong-motion data set for the 1994 Northridge earthquake. Based on this comparison, a preferred methodology is presented. Ground-motion-simulation techniques are divided into two general methods: kinematic- and composite-fault models. Green's functions of three types are evaluated: stochastic, empirical, and theoretical. A hybrid scheme is found to give the best fit to the Northridge data. Low frequencies ( 1 Hz) are calculated using a composite-fault model with a fractal subevent size distribution and stochastic, bandlimited, white-noise Green's functions. At frequencies below 1 Hz, theoretical elastic-wave-propagation synthetics introduce proper seismic-phase arrivals of body waves and surface waves. The 3D velocity structure more accurately reproduces record durations for the deep sedimentary basin structures found in the Los Angeles region. At frequencies above 1 Hz, scattering effects become important and wave propagation is more accurately represented by stochastic Green's functions. A fractal subevent size distribution for the composite fault model ensures an ??-2 spectral shape over the entire frequency band considered (0.1-20 Hz).

  18. Estimation of Source and Attenuation Parameters from Ground Motion Observations for Induced Seismicity in Alberta

    NASA Astrophysics Data System (ADS)

    Novakovic, M.; Atkinson, G. M.

    2015-12-01

    We use a generalized inversion to solve for site response, regional source and attenuation parameters, in order to define a region-specific ground-motion prediction equation (GMPE) from ground motion observations in Alberta, following the method of Atkinson et al. (2015 BSSA). The database is compiled from over 200 small to moderate seismic events (M 1 to 4.2) recorded at ~50 regional stations (distances from 30 to 500 km), over the last few years; almost all of the events have been identified as being induced by oil and gas activity. We remove magnitude scaling and geometric spreading functions from observed ground motions and invert for stress parameter, regional attenuation and site amplification. Resolving these parameters allows for the derivation of a regionally-calibrated GMPE that can be used to accurately predict amplitudes across the region in real time, which is useful for ground-motion-based alerting systems and traffic light protocols. The derived GMPE has further applications for the evaluation of hazards from induced seismicity.

  19. Near-fault earthquake ground motion prediction by a high-performance spectral element numerical code

    SciTech Connect

    Paolucci, Roberto; Stupazzini, Marco

    2008-07-08

    Near-fault effects have been widely recognised to produce specific features of earthquake ground motion, that cannot be reliably predicted by 1D seismic wave propagation modelling, used as a standard in engineering applications. These features may have a relevant impact on the structural response, especially in the nonlinear range, that is hard to predict and to be put in a design format, due to the scarcity of significant earthquake records and of reliable numerical simulations. In this contribution a pilot study is presented for the evaluation of seismic ground-motions in the near-fault region, based on a high-performance numerical code for 3D seismic wave propagation analyses, including the seismic fault, the wave propagation path and the near-surface geological or topographical irregularity. For this purpose, the software package GeoELSE is adopted, based on the spectral element method. The set-up of the numerical benchmark of 3D ground motion simulation in the valley of Grenoble (French Alps) is chosen to study the effect of the complex interaction between basin geometry and radiation mechanism on the variability of earthquake ground motion.

  20. Empirical predictive model for the vmax/ amax ratio of strong ground motions using genetic programming

    NASA Astrophysics Data System (ADS)

    Jafarian, Yaser; Kermani, Elnaz; Baziar, Mohammad H.

    2010-12-01

    Earthquake-induced deformation of structures is strongly influenced by the frequency content of input motion. Nevertheless, state-of-the-practice studies commonly use the intensity measures such as peak ground acceleration ( PGA), which are not frequency dependent. The vmax/ amax ratio of strong ground motions can be used in seismic hazard studies as a parameter that captures the influence of frequency content. In the present study, genetic programming (GP) is employed to develop a new empirical predictive equation for the vmax/ amax ratio of the shallow crustal strong ground motions recorded at free field sites. The proposed model is a function of earthquake magnitude, closest distance from source to site ( Rclstd), faulting mechanism, and average shear wave velocity over the top 30 m of site ( Vs30 ). A wide-ranging database of strong ground motion released by Pacific Earthquake Engineering Research Center (PEER) was utilized. It is demonstrated that residuals of the final equation show insignificant bias against the variations of the predictive parameters. The results indicate that vmax/ amax increases through increasing earthquake magnitude and source-to-site distance while magnitude dependency is considerably more than distance dependency. In addition, the proposed model predicts higher vmax/ amax ratio at softer sites that possess higher fundamental periods. Consequently, as an instance for the application of the proposed model, its reasonable performance in liquefaction potential assessment of sands and silty sands is presented.

  1. Widespread ground motion distribution caused by rupture directivity during the 2015 Gorkha, Nepal earthquake

    PubMed Central

    Koketsu, Kazuki; Miyake, Hiroe; Guo, Yujia; Kobayashi, Hiroaki; Masuda, Tetsu; Davuluri, Srinagesh; Bhattarai, Mukunda; Adhikari, Lok Bijaya; Sapkota, Soma Nath

    2016-01-01

    The ground motion and damage caused by the 2015 Gorkha, Nepal earthquake can be characterized by their widespread distributions to the east. Evidence from strong ground motions, regional acceleration duration, and teleseismic waveforms indicate that rupture directivity contributed significantly to these distributions. This phenomenon has been thought to occur only if a strike-slip or dip-slip rupture propagates to a site in the along-strike or updip direction, respectively. However, even though the earthquake was a dip-slip faulting event and its source fault strike was nearly eastward, evidence for rupture directivity is found in the eastward direction. Here, we explore the reasons for this apparent inconsistency by performing a joint source inversion of seismic and geodetic datasets, and conducting ground motion simulations. The results indicate that the earthquake occurred on the underthrusting Indian lithosphere, with a low dip angle, and that the fault rupture propagated in the along-strike direction at a velocity just slightly below the S-wave velocity. This low dip angle and fast rupture velocity produced rupture directivity in the along-strike direction, which caused widespread ground motion distribution and significant damage extending far eastwards, from central Nepal to Mount Everest. PMID:27335317

  2. Widespread ground motion distribution caused by rupture directivity during the 2015 Gorkha, Nepal earthquake.

    PubMed

    Koketsu, Kazuki; Miyake, Hiroe; Guo, Yujia; Kobayashi, Hiroaki; Masuda, Tetsu; Davuluri, Srinagesh; Bhattarai, Mukunda; Adhikari, Lok Bijaya; Sapkota, Soma Nath

    2016-01-01

    The ground motion and damage caused by the 2015 Gorkha, Nepal earthquake can be characterized by their widespread distributions to the east. Evidence from strong ground motions, regional acceleration duration, and teleseismic waveforms indicate that rupture directivity contributed significantly to these distributions. This phenomenon has been thought to occur only if a strike-slip or dip-slip rupture propagates to a site in the along-strike or updip direction, respectively. However, even though the earthquake was a dip-slip faulting event and its source fault strike was nearly eastward, evidence for rupture directivity is found in the eastward direction. Here, we explore the reasons for this apparent inconsistency by performing a joint source inversion of seismic and geodetic datasets, and conducting ground motion simulations. The results indicate that the earthquake occurred on the underthrusting Indian lithosphere, with a low dip angle, and that the fault rupture propagated in the along-strike direction at a velocity just slightly below the S-wave velocity. This low dip angle and fast rupture velocity produced rupture directivity in the along-strike direction, which caused widespread ground motion distribution and significant damage extending far eastwards, from central Nepal to Mount Everest. PMID:27335317

  3. Conditional spectrum computation incorporating multiple causal earthquakes and ground-motion prediction models

    USGS Publications Warehouse

    Lin, Ting; Harmsen, Stephen C.; Baker, Jack W.; Luco, Nicolas

    2013-01-01

    The conditional spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground-motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground-motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions, as well as the epistemic uncertainties in ground-motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are often considered in a PSHA computation. This paper presents the mathematics underlying these more precise CS calculations. Despite requiring more effort to compute than approximate calculations using a single causal earthquake and GMPM, the proposed approach produces an exact output that has a theoretical basis. To demonstrate the results of this approach and compare the exact and approximate calculations, several example calculations are performed for real sites in the western United States. The results also provide some insights regarding the circumstances under which approximate results are likely to closely match more exact results. To facilitate these more precise calculations for real applications, the exact CS calculations can now be performed for real sites in the United States using new deaggregation features in the U.S. Geological Survey hazard mapping tools. Details regarding this implementation are discussed in this paper.

  4. Lithological and rheological constraints on fault rupture scenarios for ground motion hazard prediction. Revision 1

    SciTech Connect

    Foxall, W.; Hutchings, L.; Jarpe, S.

    1994-09-01

    This paper tests a new approach to predict a range of ground motion hazard at specific sites generated by earthquakes on specific faults. The approach utilizes geodynamics to link structural, lithological and Theological descriptions of the fault zones to development of fault rupture scenarios and computation of synthetic seismograms. Faults are placed within a regional geomechanical model that is used to calculate stress conditions along the fault. The approach is based upon three hypothesis: (1) An exact solution of the representation relation that u@s empirical. Green`s functions enables very accurate computation of ground motions generated by a given rupture scenario; (2) a general description of the rupture is sufficient; and (3) the structural, lithological and Theological characteristics of a fault can be used to constrain, in advance, possible future rupture histories. Ground motion hazard here refers to three-component, full wave train descriptions of displacement, velocity, and acceleration over the frequency band 0.01 to 25 Hz. Corollaries to these hypotheses are that the range of possible fault rupture histories is narrow enough to functionally constrain the range of strong ground motion predictions, and that a discreet set of rupture histories is sufficient to span the infinite combinations possible from a given range of rupture parameters.

  5. Current plans to characterize the design basis ground motion at the Yucca Mountain, Nevada, site

    SciTech Connect

    Simecka, W.B.; Grant, T.A.; Voegele, M.D.; Cline, K.M.

    1993-09-01

    A site at Yucca Mountain Nevada is currently being studied to assess its suitability as a potential host site for the nation`s first commercial high level waste repository. The DOE has proposed a new methodology for determining design-basis ground motions that uses both deterministic and probabilistic methods. The role of the deterministic approach is primary. It provides the level of detail needed by design engineers in the characterization of ground motions. The probabilistic approach provides a logical structured procedure for integrating the range of possible earthquakes that contribute to the ground motion hazard at the site. In addition, probabilistic methods will be used as needed to provide input for the assessment of long-term repository performance. This paper discusses the local tectonic environment, potential seismic sources and their associated displacements and ground motions. It also discusses the approach to assessing the design basis earthquake for the surface and underground facilities, as well as selected examples of the use of this type of information in design activities.

  6. Earthquake Scaling and Development of Ground Motion Prediction for Earthquake Hazard Mitigation in Taiwan

    NASA Astrophysics Data System (ADS)

    Ma, K.; Yen, Y.

    2011-12-01

    For earthquake hazard mitigation toward risk management, integration study from development of source model to ground motion prediction is crucial. The simulation for high frequency component ( > 1 Hz) of strong ground motions in the near field was not well resolved due to the insufficient resolution in velocity structure. Using the small events as Green's functions (i.e. empirical Green's function (EGF) method) can resolve the problem of lack of precise velocity structure to replace the path effect evaluation. If the EGF is not available, a stochastic Green's function (SGF) method can be employed. Through characterizing the slip models derived from the waveform inversion, we directly extract the parameters needed for the ground motion prediction in the EGF method or the SGF method. The slip models had been investigated from Taiwan dense strong motion and global teleseismic data. In addition, the low frequency ( < 1 Hz) can obtained numerically by the Frequency-Wavenumber (FK) method. Thus, broadband frequency strong ground motion can be calculated by a hybrid method that combining a deterministic FK method for the low frequency simulation and the EGF or SGF method for high frequency simulation. Characterizing the definitive source parameters from the empirical scaling study can provide directly to the ground motion simulation. To give the ground motion prediction for a scenario earthquake, we compiled the earthquake scaling relationship from the inverted finite-fault models of moderate to large earthquakes in Taiwan. The studies show the significant involvement of the seismogenic depth to the development of rupture width. In addition to that, several earthquakes from blind fault show distinct large stress drop, which yield regional high PGA. According to the developing scaling relationship and the possible high stress drops for earthquake from blind faults, we further deploy the hybrid method mentioned above to give the simulation of the strong motion in

  7. Broadband Near-Field Ground Motion Simulations in 3D Scattering Media

    NASA Astrophysics Data System (ADS)

    Imperatori, Walter; Mai, Martin

    2013-04-01

    The heterogeneous nature of Earth's crust is manifested in the scattering of propagating seismic waves. In recent years, different techniques have been developed to include such phenomenon in broadband ground-motion calculations, either considering scattering as a semi-stochastic or pure stochastic process. In this study, we simulate broadband (0-10 Hz) ground motions using a 3D finite-difference wave propagation solver using several 3D media characterized by Von Karman correlation functions with different correlation lengths and standard deviation values. Our goal is to investigate scattering characteristics and its influence on the seismic wave-field at short and intermediate distances from the source in terms of ground motion parameters. We also examine other relevant scattering-related phenomena, such as the loss of radiation pattern and the directivity breakdown. We first simulate broadband ground motions for a point-source characterized by a classic omega-squared spectrum model. Fault finiteness is then introduced by means of a Haskell-type source model presenting both sub-shear and super-shear rupture speed. Results indicate that scattering plays an important role in ground motion even at short distances from the source, where source effects are thought to be dominating. In particular, peak ground motion parameters can be affected even at relatively low frequencies, implying that earthquake ground-motion simulations should include scattering also for PGV calculations. At the same time, we find a gradual loss of the source signature in the 2-5 Hz frequency range, together with a distortion of the Mach cones in case of super-shear rupture. For more complex source models and truly heterogeneous Earth, these effects may occur even at lower frequencies. Our simulations suggest that Von Karman correlation functions with correlation length between several hundred meters and few kilometers, Hurst exponent around 0.3 and standard deviation in the 5-10% range

  8. Required number of records for ASCE/SEI 7 ground-motion scaling procedure

    USGS Publications Warehouse

    Reyes, Juan C.; Kalkan, Erol

    2011-01-01

    The procedures and criteria in 2006 IBC (International Council of Building Officials, 2006) and 2007 CBC (International Council of Building Officials, 2007) for the selection and scaling ground-motions for use in nonlinear response history analysis (RHA) of structures are based on ASCE/SEI 7 provisions (ASCE, 2005, 2010). According to ASCE/SEI 7, earthquake records should be selected from events of magnitudes, fault distance, and source mechanisms that comply with the maximum considered earthquake, and then scaled so that the average value of the 5-percent-damped response spectra for the set of scaled records is not less than the design response spectrum over the period range from 0.2Tn to 1.5Tn sec (where Tn is the fundamental vibration period of the structure). If at least seven ground-motions are analyzed, the design values of engineering demand parameters (EDPs) are taken as the average of the EDPs determined from the analyses. If fewer than seven ground-motions are analyzed, the design values of EDPs are taken as the maximum values of the EDPs. ASCE/SEI 7 requires a minimum of three ground-motions. These limits on the number of records in the ASCE/SEI 7 procedure are based on engineering experience, rather than on a comprehensive evaluation. This study statistically examines the required number of records for the ASCE/SEI 7 procedure, such that the scaled records provide accurate, efficient, and consistent estimates of" true" structural responses. Based on elastic-perfectly-plastic and bilinear single-degree-of-freedom systems, the ASCE/SEI 7 scaling procedure is applied to 480 sets of ground-motions. The number of records in these sets varies from three to ten. The records in each set were selected either (i) randomly, (ii) considering their spectral shapes, or (iii) considering their spectral shapes and design spectral-acceleration value, A(Tn). As compared to benchmark (that is, "true") responses from unscaled records using a larger catalog of ground-motions

  9. Linear Ground-Motions in the Wabash Valley, Central United States: Two Decades of Unconventional Observations

    NASA Astrophysics Data System (ADS)

    Woolery, E. W.

    2012-12-01

    Since the mid-1980's small and moderate-sized earthquakes in the Ohio and Wabash River valleys of the central United States have been digitally recorded by seismographs, called blast monitors, deployed to monitor vibrations from chemical explosions associated with regional mining and quarrying. Because there were relatively few conventional networked strong-motion and broad-band instruments for this area between 1980 and the early 2000's, the more than 200 observations have provided a relatively widespread source of digital earthquake ground motions. Additional deployment of networked instrumentation during the last decade and their numerous recordings of the April 2008, Mt. Carmel, Illinois earthquake sequence have provided the first effective means for comparing free-field blast monitor and conventional network ground-motion observations. The peak ground-motion characteristics for both data sets relative to a common predictive relationship are similar, suggesting that blast monitor observations in the central U.S. compliment conventional network data for moderate-sized (< M5.5) events. Much of the ground motion prediction effort in the central United States has been focused on deep (>> 30 m) alluvial sites, such as those found in the Mississippi embayment. The free-field digital velocity records at blast-monitor sites in the Wabash Valley are more typical of the areas outside the embayment. The ground-motion database is composed of small to moderate size regional earthquakes with a magnitude range between M3 and M5.2; however, the bulk of the observations are associated with the 1987 M4.96 and 2008 M5.2 southeastern Illinois earthquakes, and the 2002 M4.5 southwestern Indiana earthquake. The velocity recordings and ancillary site investigations for the 2008 southeastern Illinois earthquake sequence put the findings into context with the previous observations, and quantify the reduction in ground-motion variability that can be achieved with conventional site

  10. A New Ground Motion Intensity Measure, Peak Filtered Acceleration (PFA), to Estimate Collapse Vulnerability of Buildings in Earthquakes

    NASA Astrophysics Data System (ADS)

    Song, Shiyan

    In this thesis, we develop an efficient collapse prediction model, the PFA (Peak Filtered Acceleration) model, for buildings subjected to different types of ground motions. For the structural system, the PFA model covers modern steel and reinforced concrete moment-resisting frame buildings (potentially reinforced concrete shear wall buildings). For ground motions, the PFA model covers ramp-pulse-like ground motions, long-period ground motions, and short-period ground motions. To predict whether a building will collapse in response to a given ground motion, we first extract long-period components from the ground motion using a Butterworth low-pass filter with suggested order and cutoff frequency. The order depends on the type of ground motion, and the cutoff frequency depends on the building's natural frequency and ductility. We then compare the filtered acceleration time history with the capacity of the building. The capacity of the building is a constant for 2-dimentional buildings and a limit domain for 3-dimentional buildings. If the filtered acceleration exceeds the building's capacity, the building is predicted to collapse. Otherwise, it is expected to survive the ground motion. The parameters used in PFA model, which include fundamental period, global ductility and lateral capacity, can be obtained either from numerical analysis or interpolation based on the reference building system proposed in this thesis. The PFA collapse prediction model greatly reduces computational complexity while archiving good accuracy. It is verified by FEM simulations of 13 frame building models and 150 ground motion records. Based on the developed collapse prediction model, we propose to use PFA (Peak Filtered Acceleration) as a new ground motion intensity measure for collapse prediction. We compare PFA with traditional intensity measures PGA, PGV, PGD, and Sa in collapse prediction and find that PFA has the best performance among all the intensity measures. We also provide a

  11. Uncertainty of earthquake losses due to model uncertainty of input ground motions in the Los Angeles area

    USGS Publications Warehouse

    Cao, T.; Petersen, M.D.

    2006-01-01

    In a recent study we used the Monte Carlo simulation method to evaluate the ground-motion uncertainty of the 2002 update of the California probabilistic seismic hazard model. The resulting ground-motion distribution is used in this article to evaluate the contribution of the hazard model to the uncertainty in earthquake loss ratio, the ratio of the expected loss to the total value of a structure. We use the Hazards U.S. (HAZUS) methodology for loss estimation because it is a widely used and publicly available risk model and intended for regional studies by public agencies and for use by governmental decision makers. We found that the loss ratio uncertainty depends not only on the ground-motion uncertainty but also on the mean ground-motion level. The ground-motion uncertainty, as measured by the coefficient of variation (COV), is amplified when converting to the loss ratio uncertainty because loss increases concavely with ground motion. By comparing the ground-motion uncertainty with the corresponding loss ratio uncertainty for the structural damage of light wood-frame buildings in Los Angeles area, we show that the COV of loss ratio is almost twice the COV of ground motion with a return period of 475 years around the San Andreas fault and other major faults in the area. The loss ratio for the 2475-year ground-motion maps is about a factor of three higher than for the 475-year maps. However, the uncertainties in ground motion and loss ratio for the longer return periods are lower than for the shorter return periods because the uncertainty parameters in the hazard logic tree are independent of the return period, but the mean ground motion increases with return period.

  12. Validation of Broadband Ground Motion Simulations for Japanese Crustal Earthquakes by the Recipe

    NASA Astrophysics Data System (ADS)

    Iwaki, A.; Maeda, T.; Morikawa, N.; Miyake, H.; Fujiwara, H.

    2015-12-01

    The Headquarters for Earthquake Research Promotion (HERP) of Japan has organized the broadband ground motion simulation method into a standard procedure called the "recipe" (HERP, 2009). In the recipe, the source rupture is represented by the characterized source model (Irikura and Miyake, 2011). The broadband ground motion time histories are computed by a hybrid approach: the 3-D finite-difference method (Aoi et al. 2004) and the stochastic Green's function method (Dan and Sato, 1998; Dan et al. 2000) for the long- (> 1 s) and short-period (< 1 s) components, respectively, using the 3-D velocity structure model. As the engineering significance of scenario earthquake ground motion prediction is increasing, thorough verification and validation are required for the simulation methods. This study presents the self-validation of the recipe for two MW6.6 crustal events in Japan, the 2000 Tottori and 2004 Chuetsu (Niigata) earthquakes. We first compare the simulated velocity time series with the observation. Main features of the velocity waveforms, such as the near-fault pulses and the large later phases on deep sediment sites are well reproduced by the simulations. Then we evaluate 5% damped pseudo acceleration spectra (PSA) in the framework of the SCEC Broadband Platform (BBP) validation (Dreger et al. 2015). The validation results are generally acceptable in the period range 0.1 - 10 s, whereas those in the shortest period range (0.01-0.1 s) are less satisfactory. We also evaluate the simulations with the 1-D velocity structure models used in the SCEC BBP validation exercise. Although the goodness-of-fit parameters for PSA do not significantly differ from those for the 3-D velocity structure model, noticeable differences in velocity waveforms are observed. Our results suggest the importance of 1) well-constrained 3-D velocity structure model for broadband ground motion simulations and 2) evaluation of time series of ground motion as well as response spectra.

  13. Seismic Wave Amplification in Las Vegas: Site Response and Empirical Estimates of Ground Motion

    NASA Astrophysics Data System (ADS)

    Rodgers, A.; McCallen, D.; Tkalcic, H.; Wagoner, J.; Louie, J.; Anderson, J.; Luke, B.; Snelson, C.; Taylor, W.

    2004-12-01

    This presentation will summarize a multidisciplinary effort to understand seismic wave amplification in Las Vegas Valley. The project involves weak motion recording and analysis, geotechnical and seismic refraction field studies, geologic and lithologic interpretation and model building. We will provide a brief overview of the project, then focus on specifics of seismic wave amplification including observations and interpretations. We analyzed recordings of nuclear explosions from the Nevada Test Site (NTS) and regional earthquakes to estimate site response in Las Vegas. An empirical transfer function method was used to transform ground motion time-series at one (reference) station to other stations, using frequency dependent site response curves in the band 0.2-5.0 Hz. The method transforms the time-series to the frequency domain by Fast Fourier transform, multiplies the amplitude spectrum by the site response curve and inverse FFT's back to the time domain. The approach is validated by the ability to predict horizontal component S-wave ground motion measures, such as peak and rms ground velocities and accelerations. We then can provide empirical estimates of ground motion for a wider distribution of sites in Las Vegas. Frequency dependent amplifications (site response) and peak ground motions are strongly correlated with measures of shallow shear-wave (geotechnical) velocities. Details of the geotechnical measurements and models will be presented in a companion presentation. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  14. Ground motion prediction for the Vienna Basin area using the ambient seismic field

    NASA Astrophysics Data System (ADS)

    Schippkus, Sven; Zigone, Dimitri; Bokelmann, Götz; AlpArray Working Group

    2016-04-01

    The Vienna Basin is one of the most seismically active regions in Austria. Because of the population density and sensitive infrastructure, seismic hazard assessment in this area is of critical importance. An important part of seismic hazard analysis is ground motion prediction, which can in principle be done using either empirical studies to derive ground motion prediction equations (GMPEs) or using a physics-based approach to simulate ground motion by modelling surface wave propagation. Recently a new method has been presented that is based on the emergence of the inter-station Green's function from ambient noise cross-correlations (Denolle et al. 2013), which provides the impulse response of the Earth from a point source at the surface (from the site of one of the two receivers to the other). These impulse responses are dominated by surface waves, which would, in the case of a real earthquake, cause the major damages. The Green's function can in principle be modified to simulate a double couple dislocation at depth, i.e., a virtual earthquake. Using an adapted pre-processing method, the relative amplitudes of the ambient noise records of different inter-station paths are preserved in the correlation functions, and effects like attenuation and amplification of surface waves in sedimentary basins can be studied. This provides more precise information that will help improve seismic hazard evaluations. Here we present a preliminary study of such ground motion prediction for the Vienna Basin using about two dozen broadband stations from available networks in the area, e.g., stations from the University of Vienna (AlpArray) and Vienna Technical University. References Denolle, M. A., E. M. Dunham, G. A. Prieto, and G. C. Beroza (2013), Ground motion prediction of realistic earthquake sources using the ambient seismic field, J. Geophys. Res. Solid Earth, 118, 2102-2118, doi:10.1029/2012JB009603.

  15. Ground motion optimized orbit feedback design for the future linear collider

    NASA Astrophysics Data System (ADS)

    Pfingstner, J.; Snuverink, J.; Schulte, D.

    2013-03-01

    The future linear collider has strong stability requirements on the position of the beam along the accelerator and at the interaction point (IP). The beam position will be sensitive to dynamic imperfections in particular ground motion. A number of mitigation techniques have been proposed to be deployed in parallel: active and passive quadrupole stabilization and positioning as well as orbit and IP feedback. This paper presents a novel design of the orbit controller in the main linac and beam delivery system. One global feedback controller is proposed based on an SVD-controller (Singular Value Decomposition) that decouples the large multi-input multi-output system into many independent single-input single-output systems. A semi-automatic procedure is proposed for the controller design of the independent systems by exploiting numerical models of ground motion and measurement noise to minimize a target parameter, e.g. luminosity loss. The novel design for the orbit controller is studied for the case of the Compact Linear Collider (CLIC) in integrated simulations, which include all proposed mitigation methods. The impact of the ground motion on the luminosity performance is examined in detail. It is shown that with the proposed orbit controller the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed. The orbit controller design is robust and allows for a relaxed BPM resolution, while still maintaining a strong ground motion suppression performance compared to traditional methods. We believe that the described method could easily be applied to other accelerators and light sources.

  16. The Engineering Strong Ground Motion Network of the National Autonomous University of Mexico

    NASA Astrophysics Data System (ADS)

    Velasco Miranda, J. M.; Ramirez-Guzman, L.; Aguilar Calderon, L. A.; Almora Mata, D.; Ayala Hernandez, M.; Castro Parra, G.; Molina Avila, I.; Mora, A.; Torres Noguez, M.; Vazquez Larquet, R.

    2014-12-01

    The coverage, design, operation and monitoring capabilities of the strong ground motion program at the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM) is presented. Started in 1952, the seismic instrumentation intended initially to bolster earthquake engineering projects in Mexico City has evolved into the largest strong ground motion monitoring system in the region. Today, it provides information not only to engineering projects, but also to the near real-time risk mitigation systems of the country, and enhances the general understanding of the effects and causes of earthquakes in Mexico. The IE network includes more than 100 free-field stations and several buildings, covering the largest urban centers and zones of significant seismicity in Central Mexico. Of those stations, approximately one-fourth send the observed acceleration to a processing center in Mexico City continuously, and the rest require either periodic visits for the manual recovery of the data or remote interrogation, for later processing and cataloging. In this research, we document the procedures and telecommunications systems used systematically to recover information. Additionally, we analyze the spatial distribution of the free-field accelerographs, the quality of the instrumentation, and the recorded ground motions. The evaluation criteria are based on the: 1) uncertainty in the generation of ground motion parameter maps due to the spatial distribution of the stations, 2) potential of the array to provide localization and magnitude estimates for earthquakes with magnitudes greater than Mw 5, and 3) adequacy of the network for the development of Ground Motion Prediction Equations due to intra-plate and intra-slab earthquakes. We conclude that the monitoring system requires a new redistribution, additional stations, and a substantial improvement in the instrumentation and telecommunications. Finally, we present an integral plan to improve the current network

  17. Modelling of the Seismic Ground Motion in Barquisimeto and Cabudare cities

    NASA Astrophysics Data System (ADS)

    Alvarado, L.; Alvarez, L.; Rocabado, V.; Schmitz, M.; Granado, C.; Rendon, H.

    2007-05-01

    A 2D modeling of the seismic response is obtained using modeling techniques that allow the computation of synthetic seismograms, corresponding to two different seismic source models. The application of the modal summation technique, extended to laterally heterogeneous structural models, to the area of Barquisimeto and Cabudare allows us to create synthetic seismograms that can be used for the study of the local response along of four profiles The calculation has been made by a hybrid method: Modal summation in the regional anelastic mode (1D) where the source is located, and the finite difference in the local sedimentary structure (2D). The realistic modeling of ground motion is a very important base of knowledge for the preparation of ground shaking scenarios, as well as for the assessment of ground motion parameters for seismic microzonation.

  18. Motion parameter estimation of multiple ground moving targets in multi-static passive radar systems

    NASA Astrophysics Data System (ADS)

    Subedi, Saurav; Zhang, Yimin D.; Amin, Moeness G.; Himed, Braham

    2014-12-01

    Multi-static passive radar (MPR) systems typically use narrowband signals and operate under weak signal conditions, making them difficult to reliably estimate motion parameters of ground moving targets. On the other hand, the availability of multiple spatially separated illuminators of opportunity provides a means to achieve multi-static diversity and overall signal enhancement. In this paper, we consider the problem of estimating motion parameters, including velocity and acceleration, of multiple closely located ground moving targets in a typical MPR platform with focus on weak signal conditions, where traditional time-frequency analysis-based methods become unreliable or infeasible. The underlying problem is reformulated as a sparse signal reconstruction problem in a discretized parameter search space. While the different bistatic links have distinct Doppler signatures, they share the same set of motion parameters of the ground moving targets. Therefore, such motion parameters act as a common sparse support to enable the exploitation of group sparsity-based methods for robust motion parameter estimation. This provides a means of combining signal energy from all available illuminators of opportunity and, thereby, obtaining a reliable estimation even when each individual signal is weak. Because the maximum likelihood (ML) estimation of motion parameters involves a multi-dimensional search and its performance is sensitive to target position errors, we also propose a technique that decouples the target motion parameters, yielding a two-step process that sequentially estimates the acceleration and velocity vectors with a reduced dimensionality of the parameter search space. We compare the performance of the sequential method against the ML estimation with the consideration of imperfect knowledge of the initial target positions. The Cramér-Rao bound (CRB) of the underlying parameter estimation problem is derived for a general multiple-target scenario in an MPR system

  19. Generation of a mixture model ground-motion prediction equation for Northern Chile

    NASA Astrophysics Data System (ADS)

    Haendel, A.; Kuehn, N. M.; Scherbaum, F.

    2012-12-01

    In probabilistic seismic hazard analysis (PSHA) empirically derived ground motion prediction equations (GMPEs) are usually applied to estimate the ground motion at a site of interest as a function of source, path and site related predictor variables. Because GMPEs are derived from limited datasets they are not expected to give entirely accurate estimates or to reflect the whole range of possible future ground motion, thus giving rise to epistemic uncertainty in the hazard estimates. This is especially true for regions without an indigenous GMPE where foreign models have to be applied. The choice of appropriate GMPEs can then dominate the overall uncertainty in hazard assessments. In order to quantify this uncertainty, the set of ground motion models used in a modern PSHA has to capture (in SSHAC language) the center, body, and range of the possible ground motion at the site of interest. This was traditionally done within a logic tree framework in which existing (or only slightly modified) GMPEs occupy the branches of the tree and the branch weights describe the degree-of-belief of the analyst in their applicability. This approach invites the problem to combine GMPEs of very different quality and hence to potentially overestimate epistemic uncertainty. Some recent hazard analysis have therefore resorted to using a small number of high quality GMPEs as backbone models from which the full distribution of GMPEs for the logic tree (to capture the full range of possible ground motion uncertainty) where subsequently generated by scaling (in a general sense). In the present study, a new approach is proposed to determine an optimized backbone model as weighted components of a mixture model. In doing so, each GMPE is assumed to reflect the generation mechanism (e. g. in terms of stress drop, propagation properties, etc.) for at least a fraction of possible ground motions in the area of interest. The combination of different models into a mixture model (which is learned from

  20. Characteristics of strong ground motions in the 2014 M s 6.5 Ludian earthquake, Yunnan, China

    NASA Astrophysics Data System (ADS)

    Hu, J. J.; Zhang, Q.; Jiang, Z. J.; Xie, L. L.; Zhou, B. F.

    2016-01-01

    The 2014 M s 6.5 ( M w6.1) Ludian earthquake occurred in the eastern Sichuan-Yunnan border region of western China. This earthquake caused much more severe engineering damage than the usual earthquakes with the same magnitude in China. The National Strong Motion Network obtained large set of ground motion recordings during the earthquake. To investigate the engineering interested characteristics of ground motion from Ludian earthquake and compare it with the M w 7.9 Wenchuan and the M w 6.6 Lushan earthquakes in western China, studies on the ground motion field, attenuation relationship, distance dependence of significant duration, and site amplification were carried out. Some conclusion is drawn. Specifically, the ground motion field reveals a directional feature, and the distribution characteristics of the two horizontal components are similar. The attenuation relationship for Ludian earthquake is basically consistent with the ground motion prediction equation (GMPE) for western China, except the slight smaller than the GMPE predicted at short periods. The distance dependences of ground motion duration are different in Sichuan and Yunnan regions due to the local physical dispersion and Q value. The site amplification factors are dominated by linear site response for lower reference ground motion, but the nonlinearity becomes notable for higher reference ground motion. This feature is basically consistent with the empirical model for western China. All the results indicate that the spatial distribution of ground motion, the attenuation characteristics, and the site amplification effect should be considered in characterization of near-field ground motion.

  1. Earthquake scenario ground motions for the urban area of Evansville, Indiana

    USGS Publications Warehouse

    Haase, Jennifer S.; Nowack, Robert L.; Cramer, Chris H.; Boyd, Oliver S.; Bauer, Robert A.

    2011-01-01

    The Wabash Valley seismic zone and the New Madrid seismic zone are the closest large earthquake source zones to Evansville, Indiana. The New Madrid earthquakes of 1811-1812, over 180 kilometers (km) from Evansville, produced ground motions with a Modified Mercalli Intensity of VII near Evansville, the highest intensity observed in Indiana. Liquefaction evidence has been documented less than 40 km away from Evansville resulting from two large earthquakes in the past 12,000 years in the Wabash Valley. Two earthquake scenarios are described in this paper that demonstrate the expected ground motions for a 33×42-km region around Evansville based on a repeat earthquake from each of these source regions. We perform a one-dimensional analysis for a grid of sites that takes into account the amplification or deamplification of ground motion in the unconsolidated soil layer using a new three-dimensional model of seismic velocity and bedrock depth. There are significant differences in the calculated amplification from that expected for National Earthquake Hazard Reduction Program site class D conditions, with deamplification at many locations within the ancient bedrock valley underlying Evansville. Ground motions relative to the acceleration of gravity (g) in the Evansville area from a simulation of a magnitude (M) 7.7 New Madrid earthquake range from 0.15 to 0.25 g for peak ground acceleration, 0.14 to 0.7 g for 0.2-second (s) spectral acceleration, and 0.05 to 0.25 g for 1.0-s spectral acceleration. Ground motions from a M6.8 Wabash Valley earthquake centered 40 km northwest of the city produce ground motions that decrease with distance from 1.5 to 0.3 g for 0.2-s spectral acceleration when they reach the main part of Evansville, but then increase in amplitude from 0.3 to 0.6 g south of the city and the Ohio River. The densest urbanization in Evansville and Henderson, Ky., is within the area of preferential amplification at 1.0-s period for both scenarios, but the area

  2. Near-source ground motions from simulations of sustained intersonic and supersonic fault ruptures

    USGS Publications Warehouse

    Aagaard, B.T.; Heaton, T.H.

    2004-01-01

    We examine the long-period near-source ground motions from simulations of M 7.4 events on a strike-slip fault using kinematic ruptures with rupture speeds that range from subshear speeds through intersonic speeds to supersonic speeds. The strong along-strike shear-wave directivity present in scenarios with subshear rupture speeds disappears in the scenarios with ruptures propagating faster than the shear-wave speed. Furthermore, the maximum horizontal displacements and velocities rotate from generally fault-perpendicular orientations at subshear rupture speeds to generally fault-parallel orientations at supersonic rupture speeds. For rupture speeds just above the shear-wave speed, the orientations are spatially heterogeneous as a result of the random nature of our assumed slip model. At locations within a few kilometers of the rupture, the time histories of the polarization of the horizontal motion provide a better diagnostic with which to gauge the rupture speed than the orientation of the peak motion. Subshear ruptures are associated with significant fault-perpendicular motion before fault-parallel motion close to the fault; supershear ruptures are associated with fault-perpendicular motion after significant fault-parallel motion. Consistent with previous studies, we do not find evidence for prolonged supershear rupture in the long-period (>2 sec) ground motions from the 1979 Imperial Valley earthquake. However, we are unable to resolve the issue of whether a limited portion of the rupture (approximately 10 km in length) propagated faster than the shear-wave speed. Additionally, a recording from the 2002 Denali fault earthquake does appear to be qualitatively consistent with locally supershear rupture. Stronger evidence for supershear rupture in earthquakes may require very dense station coverage in order to capture these potentially distinguishing traits.

  3. Strong ground motion in the Kathmandu Valley during the 2015 Gorkha, Nepal, earthquake

    NASA Astrophysics Data System (ADS)

    Takai, Nobuo; Shigefuji, Michiko; Rajaure, Sudhir; Bijukchhen, Subeg; Ichiyanagi, Masayoshi; Dhital, Megh Raj; Sasatani, Tsutomu

    2016-01-01

    On 25 April 2015, a large earthquake of Mw 7.8 occurred along the Main Himalayan Thrust fault in central Nepal. It was caused by a collision of the Indian Plate beneath the Eurasian Plate. The epicenter was near the Gorkha region, 80 km northwest of Kathmandu, and the rupture propagated toward east from the epicentral region passing through the sediment-filled Kathmandu Valley. This event resulted in over 8000 fatalities, mostly in Kathmandu and the adjacent districts. We succeeded in observing strong ground motions at our four observation sites (one rock site and three sedimentary sites) in the Kathmandu Valley during this devastating earthquake. While the observed peak ground acceleration values were smaller than the predicted ones that were derived from the use of a ground motion prediction equation, the observed peak ground velocity values were slightly larger than the predicted ones. The ground velocities observed at the rock site (KTP) showed a simple velocity pulse, resulting in monotonic-step displacements associated with the permanent tectonic offset. The vertical ground velocities observed at the sedimentary sites had the same pulse motions that were observed at the rock site. In contrast, the horizontal ground velocities as well as accelerations observed at three sedimentary sites showed long duration with conspicuous long-period oscillations, due to the valley response. The horizontal valley response was characterized by large amplification (about 10) and prolonged oscillations. However, the predominant period and envelope shape of their oscillations differed from site to site, indicating a complicated basin structure. Finally, on the basis of the velocity response spectra, we show that the horizontal long-period oscillations on the sedimentary sites had enough destructive power to damage high-rise buildings with natural periods of 3 to 5 s.

  4. Strong ground-motion prediction from Stochastic-dynamic source models

    USGS Publications Warehouse

    Guatteri, Mariagiovanna; Mai, P.M.; Beroza, G.C.; Boatwright, J.

    2003-01-01

    In the absence of sufficient data in the very near source, predictions of the intensity and variability of ground motions from future large earthquakes depend strongly on our ability to develop realistic models of the earthquake source. In this article we simulate near-fault strong ground motion using dynamic source models. We use a boundary integral method to simulate dynamic rupture of earthquakes by specifying dynamic source parameters (fracture energy and stress drop) as spatial random fields. We choose these quantities such that they are consistent with the statistical properties of slip heterogeneity found in finite-source models of past earthquakes. From these rupture models we compute theoretical strong-motion seismograms up to a frequency of 2 Hz for several realizations of a scenario strike-slip Mw 7.0 earthquake and compare empirical response spectra, spectra obtained from our dynamic models, and spectra determined from corresponding kinematic simulations. We find that spatial and temporal variations in slip, slip rise time, and rupture propagation consistent with dynamic rupture models exert a strong influence on near-source ground motion. Our results lead to a feasible approach to specify the variability in the rupture time distribution in kinematic models through a generalization of Andrews' (1976) result relating rupture speed to apparent fracture energy, stress drop, and crack length to 3D dynamic models. This suggests that a simplified representation of dynamic rupture may be obtained to approximate the effects of dynamic rupture without having to do full dynamic simulations.

  5. Ground Motion Simulations for Bursa Region (Turkey) Using Input Parameters derived from the Regional Seismic Network

    NASA Astrophysics Data System (ADS)

    Unal, B.; Askan, A.

    2014-12-01

    Earthquakes are among the most destructive natural disasters in Turkey and it is important to assess seismicity in different regions with the use of seismic networks. Bursa is located in Marmara Region, Northwestern Turkey and to the south of the very active North Anatolian Fault Zone. With around three million inhabitants and key industrial facilities of the country, Bursa is the fourth largest city in Turkey. Since most of the focus is on North Anatolian Fault zone, despite its significant seismicity, Bursa area has not been investigated extensively until recently. For reliable seismic hazard estimations and seismic design of structures, assessment of potential ground motions in this region is essential using both recorded and simulated data. In this study, we employ stochastic finite-fault simulation with dynamic corner frequency approach to model previous events as well to assess potential earthquakes in Bursa. To ensure simulations with reliable synthetic ground motion outputs, the input parameters must be carefully derived from regional data. In this study, using strong motion data collected at 33 stations in the region, site-specific parameters such as near-surface high frequency attenuation parameter and amplifications are obtained. Similarly, source and path parameters are adopted from previous studies that as well employ regional data. Initially, major previous events in the region are verified by comparing the records with the corresponding synthetics. Then simulations of scenario events in the region are performed. We present the results in terms of spatial distribution of peak ground motion parameters and time histories at selected locations.

  6. Pseudo-Spectral Damping Reduction Factors for the Himalayan Region Considering Recorded Ground-Motion Data.

    PubMed

    P, Anbazhagan; Uday, Anjali; Moustafa, Sayed S R; Al-Arifi, Nassir S N

    2016-01-01

    Ground-motion prediction equations that are used to predict acceleration values are generally developed for a 5% viscous damping ratio. Special structures and structures that use damping devices may have damping ratios other than the conventionally used ratio of 5%. Hence, for such structures, the intensity measures predicted by conventional ground-motion prediction equations need to be converted to a particular level of damping using a damping reduction factor (DRF). DRF is the ratio of the spectral ordinate at 5% damping to the ordinate at a defined level of damping. In this study, the DRF has been defined using the spectral ordinate of pseudo-spectral acceleration and the effect of factors such as the duration of ground motion, magnitude, hypocenter distance, site classification, damping, and period are studied. In this study, an attempt has also been made to develop an empirical model for the DRF that is specifically applicable to the Himalayan region in terms of these predictor variables. A recorded earthquake with 410 horizontal motions was used, with data characterized by magnitudes ranging from 4 to 7.8 and hypocentral distances up to 520 km. The damping was varied from 0.5-30% and the period range considered was 0.02 to 10 s. The proposed model was compared and found to coincide well with models in the existing literature. The proposed model can be used to compute the DRF at any specific period, for any given value of predictor variables. PMID:27611854

  7. 3-D or median map? Earthquake scenario ground-motion maps from physics-based models versus maps from ground-motion prediction equations

    NASA Astrophysics Data System (ADS)

    Porter, K.

    2015-12-01

    There are two common ways to create a ground-motion map for a hypothetical earthquake: using ground motion prediction equations (by far the more common of the two) and using 3-D physics-based modeling. The former is very familiar to engineers, the latter much less so, and the difference can present a problem because engineers tend to trust the familiar and distrust novelty. Maps for essentially the same hypothetical earthquake using the two different methods can look very different, while appearing to present the same information. Using one or the other can lead an engineer or disaster planner to very different estimates of damage and risk. The reasons have to do with depiction of variability, spatial correlation of shaking, the skewed distribution of real-world shaking, and the upward-curving relationship between shaking and damage. The scientists who develop the two kinds of map tend to specialize in one or the other and seem to defend their turf, which can aggravate the problem of clearly communicating with engineers.The USGS Science Application for Risk Reduction's (SAFRR) HayWired scenario has addressed the challenge of explaining to engineers the differences between the two maps, and why, in a disaster planning scenario, one might want to use the less-familiar 3-D map.

  8. Validation and modeling of earthquake strong ground motion using a composite source model

    NASA Astrophysics Data System (ADS)

    Zeng, Y.

    2001-12-01

    Zeng et al. (1994) have proposed a composite source model for synthetic strong ground motion prediction. In that model, the source is taken as a superposition of circular subevents with a constant stress drop. The number of subevents and their radius follows a power law distribution equivalent to the Gutenberg and Richter's magnitude-frequency relation for seismicity. The heterogeneous nature of the composite source model is characterized by its maximum subevent size and subevent stress drop. As rupture propagates through each subevent, it radiates a Brune's pulse or a Sato and Hirasawa's circular crack pulse. The method has been proved to be successful in generating realistic strong motion seismograms in comparison with observations from earthquakes in California, eastern US, Guerrero of Mexico, Turkey and India. The model has since been improved by including scattering waves from small scale heterogeneity structure of the earth, site specific ground motion prediction using weak motion site amplification, and nonlinear soil response using geotechnical engineering models. Last year, I have introduced an asymmetric circular rupture to improve the subevent source radiation and to provide a consistent rupture model between overall fault rupture process and its subevents. In this study, I revisit the Landers, Loma Prieta, Northridge, Imperial Valley and Kobe earthquakes using the improved source model. The results show that the improved subevent ruptures provide an improved effect of rupture directivity compared to our previous studies. Additional validation includes comparison of synthetic strong ground motions to the observed ground accelerations from the Chi-Chi, Taiwan and Izmit, Turkey earthquakes. Since the method has evolved considerably when it was first proposed, I will also compare results between each major modification of the model and demonstrate its backward compatibility to any of its early simulation procedures.

  9. Comparing stochastic point-source and finite-source ground-motion simulations: SMSIM and EXSIM

    USGS Publications Warehouse

    Boore, D.M.

    2009-01-01

    Comparisons of ground motions from two widely used point-source and finite-source ground-motion simulation programs (SMSIM and EXSIM) show that the following simple modifications in EXSIM will produce agreement in the motions from a small earthquake at a large distance for the two programs: (1) base the scaling of high frequencies on the integral of the squared Fourier acceleration spectrum; (2) do not truncate the time series from each subfault; (3) use the inverse of the subfault corner frequency for the duration of motions from each subfault; and (4) use a filter function to boost spectral amplitudes at frequencies near and less than the subfault corner frequencies. In addition, for SMSIM an effective distance is defined that accounts for geometrical spreading and anelastic attenuation from various parts of a finite fault. With these modifications, the Fourier and response spectra from SMSIM and EXSIM are similar to one another, even close to a large earthquake (M 7), when the motions are averaged over a random distribution of hypocenters. The modifications to EXSIM remove most of the differences in the Fourier spectra from simulations using pulsing and static subfaults; they also essentially eliminate any dependence of the EXSIM simulations on the number of subfaults. Simulations with the revised programs suggest that the results of Atkinson and Boore (2006), computed using an average stress parameter of 140 bars and the original version of EXSIM, are consistent with the revised EXSIM with a stress parameter near 250 bars.

  10. Ground motion prediction equations for horizontal and vertical components of acceleration in Northern Iran

    NASA Astrophysics Data System (ADS)

    Soghrat, M. R.; Ziyaeifar, M.

    2016-05-01

    Recent studies have shown that the vertical component of ground motion can be quite destructive on a variety of structural systems. Development of response spectrum for design of buildings subjected to vertical component of earthquake needs ground motion prediction equations (GMPEs). The existing GMPEs for northern Iranian plateau are proposed for the horizontal component of earthquake, and there is not any specified GMPE for the vertical component of earthquake in this region. Determination of GMPEs is mostly based on regression analyses on earthquake parameters such as magnitude, site class, distance, and spectral amplitudes. In this study, 325 three-component records of 55 earthquakes with magnitude ranging from M w 4.1 to M w 7.3 are used for estimation on the regression coefficients. Records with distances less than 300 km are selected for analyses in the database. The regression analyses on earthquake parameters results in determination of GMPEs for peak ground acceleration and spectral acceleration for both horizontal and vertical components of the ground motion. The correlation between the models for vertical and horizontal GMPEs is studied in details. These models are later compared with some other available GMPEs. According to the result of this investigation, the proposed GMPEs are in agreement with the other relationships that were developed based on the local and regional data.

  11. Ground motion values for use in the seismic design of the Trans-Alaska Pipeline system

    USGS Publications Warehouse

    Page, Robert A.; Boore, D.M.; Joyner, W.B.; Coulter, H.W.

    1972-01-01

    The proposed trans-Alaska oil pipeline, which would traverse the state north to south from Prudhoe Bay on the Arctic coast to Valdez on Prince William Sound, will be subject to serious earthquake hazards over much of its length. To be acceptable from an environmental standpoint, the pipeline system is to be designed to minimize the potential of oil leakage resulting from seismic shaking, faulting, and seismically induced ground deformation. The design of the pipeline system must accommodate the effects of earthquakes with magnitudes ranging from 5.5 to 8.5 as specified in the 'Stipulations for Proposed Trans-Alaskan Pipeline System.' This report characterizes ground motions for the specified earthquakes in terms of peak levels of ground acceleration, velocity, and displacement and of duration of shaking. Published strong motion data from the Western United States are critically reviewed to determine the intensity and duration of shaking within several kilometers of the slipped fault. For magnitudes 5 and 6, for which sufficient near-fault records are available, the adopted ground motion values are based on data. For larger earthquakes the values are based on extrapolations from the data for smaller shocks, guided by simplified theoretical models of the faulting process.

  12. Update of the Graizer-Kalkan ground-motion prediction equations for shallow crustal continental earthquakes

    USGS Publications Warehouse

    Graizer, Vladimir; Kalkan, Erol

    2015-01-01

    A ground-motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration and 5-percent damped pseudo spectral acceleration response ordinates of maximum horizontal component of randomly oriented ground motions was developed by Graizer and Kalkan (2007, 2009) to be used for seismic hazard analyses and engineering applications. This GMPE was derived from the greatly expanded Next Generation of Attenuation (NGA)-West1 database. In this study, Graizer and Kalkan’s GMPE is revised to include (1) an anelastic attenuation term as a function of quality factor (Q0) in order to capture regional differences in large-distance attenuation and (2) a new frequency-dependent sedimentary-basin scaling term as a function of depth to the 1.5-km/s shear-wave velocity isosurface to improve ground-motion predictions for sites on deep sedimentary basins. The new model (GK15), developed to be simple, is applicable to the western United States and other regions with shallow continental crust in active tectonic environments and may be used for earthquakes with moment magnitudes 5.0–8.0, distances 0–250 km, average shear-wave velocities 200–1,300 m/s, and spectral periods 0.01–5 s. Directivity effects are not explicitly modeled but are included through the variability of the data. Our aleatory variability model captures inter-event variability, which decreases with magnitude and increases with distance. The mixed-effects residuals analysis shows that the GK15 reveals no trend with respect to the independent parameters. The GK15 is a significant improvement over Graizer and Kalkan (2007, 2009), and provides a demonstrable, reliable description of ground-motion amplitudes recorded from shallow crustal earthquakes in active tectonic regions over a wide range of magnitudes, distances, and site conditions.

  13. Measuring both Rotational and Translational Ground-Motions from Explosions and Local Earthquakes in Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, B.; Lee, W.; Lin, C.; Liu, C.; Shin, T.; Teng, T.; Wu, C.

    2008-12-01

    Since rotational motions can "contaminate" translational ground-motion measurements due to the induced perturbation of the Earth's gravitational field, we started a program to measure rotational ground motions near Hualien (Taiwan) in December, 2000. However, no useful data were obtained after 3 years, until a rotational sensor of much higher sensitivity was deployed at the HGSD station in eastern Taiwan in December, 2004. Rotational and translational seismograms were obtained from several hundred local earthquakes. As noted by several authors before, we found a linear relationship between peak rotational rate (PRR in mrad/s) and peak ground acceleration (PGA in m/s2) from local earthquakes in Taiwan: PRR = 0.002 + 1.301 PGA, with a correlation coefficient of 0.988. Taking advantage of two large explosions of the TAIGER Active Seismic Experiment, we deployed 13 accelerometers and 8 rotational sensors within 600 m from the N3 shot points and obtained some interesting results, which will be presented by Langston et al. in this Session. In December, 2007, we began an instrument array deployment along the Meishan fault in southwestern Taiwan, where a major earthquake occurred in 1906 with surface rupture of more than 12 km long. The deployed instruments are: (1) a 32-element seismic array in free-field, (2) a 32-element accelerometer array in a building, (3) a six-channel unit with a low-gain broadband seismometer and an accelerometer, and (4) two six-channel units with an accelerometer and an external rotational senor. We have 8 rotational sensors now deployed in Taiwan and seven new rotational sensors are scheduled for deployment soon in a program to assess the effect of ground rotation on traditional measurements of translational strong ground motions.

  14. Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion

    USGS Publications Warehouse

    Borcherdt, Roger D.

    1994-01-01

    Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits

  15. Key elements of regional seismic velocity models for long period ground motion simulations

    USGS Publications Warehouse

    Brocher, T.M.

    2008-01-01

    Regional 3-D seismic velocity models used for broadband strong motion simulations must include compressional-wave velocity (Vp), shear-wave velocity (Vs), intrinsic attenuation (Qp, Qs), and density. Vs and Qs are the most important of these parameters because the strongest ground motions are generated chiefly by shear- and surface-wave arrivals. Because Vp data are more common than Vs data, many researchers first develop a Vp model and convert it to a Vs model. I describe recent empirical relations between Vs, Vp, Qs, Qp, and density that allow velocity models to be rapidly and accurately calculated. ?? Springer Science+Business Media B.V. 2007.

  16. The effects of structural setting on the azimuthal velocities of blast induced ground motion in perlite

    SciTech Connect

    Beattie, S.G.

    1995-02-01

    A series of small scale explosive tests were performed during the spring of 1994 at a perlite mine located near Socorro, NM. The tests were designed to investigate the azimuthal or directional relationship between small scale geologic structures such as joints and the propagation of explosively induced ground motion. Three shots were initiated within a single borehole located at ground zero (gz) at depths varying from the deepest at 83 m (272 ft) to the shallowest at 10 m (32 ft). The intermediate shot was initiated at a depth of 63 m (208 ft). An array of three component velocity and acceleration transducers were placed in two concentric rings entirely surrounding the single shot hole at 150 and 300 azimuths as measured from ground zero. Data from the transducers was then used to determine the average propagation velocity of the blast vibration through the rock mass at the various azimuths. The rock mass was mapped to determine the prominent joint orientations (strike and dip) and the average propagation velocities were correlated with this geologic information. The data from these experiments shows that there is a correlation between the orientation of prominent joints and the average velocity of ground motion. It is theorized that this relationship is due to the relative path the ground wave follows when encountering a joint or structure within the rock mass. The more prominent structures allow the wave to follow along their strike thereby forming a sort of channel or path of least resistance and in turn increasing the propagation velocity. Secondary joints or structures may act in concert with more prominent features to form a network of channels along which the wave moves more freely than it may travel against the structure. The amplitudes of the ground motion was also shown to vary azimuthally with the direction of the most prominent structures.

  17. Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States

    USGS Publications Warehouse

    Ramirez-Guzman, L.; Graves, Robert; Olsen, Kim B.; Boyd, Oliver; Cramer, Chris H.; Hartzell, Stephen; Ni, Sidao; Somerville, Paul G.; Williams, Robert; Zhong, Jinquan

    2015-01-01

    The region covered by our simulation domain encompasses a large portion of the CUS centered on the NMSZ, including several major metropolitan areas. Based on our simulations, more than eight million people living and working near the NMSZ would experience potentially damaging ground motion and modified Mercalli intensities ranging from VI to VIII if a repeat of the 1811–1812 earthquakes occurred today. Moreover, the duration of strong ground shaking in the greater Memphis metropolitan area could last from 30 to more than 60 s, depending on the magnitude and epicenter.

  18. Identifying the unique ground motion signatures of supershear earthquakes: Theory and experiments

    NASA Astrophysics Data System (ADS)

    Mello, M.; Bhat, H. S.; Rosakis, A. J.; Kanamori, H.

    2010-10-01

    The near field ground motion signatures associated with sub-Rayleigh and supershear ruptures are investigated using the laboratory earthquake experiment originally developed by Rosakis and coworkers (Xia et al., 2004, 2005a; Lu et al., 2007; Rosakis et al., 2007). Heterodyne laser interferometers enable continuous, high bandwidth measurements of fault-normal (FN) and fault-parallel (FP) particle velocity "ground motion" records at discrete locations on the surface of a Homalite test specimen as a sub-Rayleigh or a supershear rupture sweeps along the frictional fault. Photoelastic interference fringes, acquired using high-speed digital photography, provide a synchronized, spatially resolved, whole field view of the advancing rupture tip and surrounding maximum shear stress field. Experimental results confirm that near field ground motion records associated with the passage of a sub-Rayleigh rupture are characterized by a FN velocity swing which dominates over the FP velocity swing. The situation is shown to reverse in the supershear rupture speed regime whereby the motion along the shear Mach front is characterized by a FP particle velocity swing which dominates over the FN velocity swing. Additional distinguishing particle velocity signatures, consistent with theoretical and numerical predictions, and repeatedly observed in experimental records are (1) a pronounced peak in the FP velocity record, induced by the leading dilatational field, which sweeps the measurement station just prior to the arrival of the shear Mach front, and (2) a pronounced velocity swing in the FN record associated with the arrival of a "trailing Rayleigh disturbance", which sweeps the measurement station following passage of the shear Mach front. Each of these features are addressed in detail. We conclude by reexamining the 2002, Mw7.9 Denali fault earthquake and the remarkable set of ground motion records obtained at Pump Station 10 (PS10), located approximately 85 km east of the epicenter

  19. Distance-dependent Ground motion variability from source models of the 1992 Landers earthquake and synthetic rupture models.

    NASA Astrophysics Data System (ADS)

    Vyas, J. C.; Mai, P. M.; Galis, M.

    2014-12-01

    We investigate near field ground motion variability due to five different kinematic rupture models for 1992 Landers earthquake. The ground motion simulations are accomplished by solving the elasto-dynamic equations of motion using a generalized finite-difference method (Ely et al., 2008). Simulated waveforms are calibrated against near-field strong-motion recordings. We then analyze a large data-set of ground-motions from 2000 sites, binned with respect to distance and azimuth to compute mean and standard deviation of peak ground velocity (PGV). We consider 1D-velocity structures as used in the source inversions, and honor the geometrical complexity due to fault segmentation. Our simulations reveal that ground motion variability is reduced as the distance from the fault increases. Variability in the kinematic sources has considerable impact on the resulting shaking variability, although the five source models considered are derived by inversion of seismic and/or geodetic data. Simulated mean PGV and its standard deviation are comparable to empirical estimates using the ground-motion prediction equation (GMPE) of Boore and Atkinson (2008). In addition, we find that intra-event ground motion variability is large in fault-parallel and small in fault-normal direction. We also compare our simulations with and without Spudich and Chiou (2008) directivity corrections, applied to Boore and Atkinson (2008), which shows that slip heterogeneity controls near-field ground-motion variability. We further investigate the effect of slip heterogeneity by considering eleven (ten heterogeneous and one uniform) synthetic rupture models. Heterogeneous slip models are generated following the algorithm of Mai and Beroza (2002) for different correlation lengths and Hurst exponents. We then examine synthetic seismograms calculated at 1500 stations for the eleven rupture models, confirming that the distance decay of ground motion variability is due to slip heterogeneity.

  20. Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media

    NASA Astrophysics Data System (ADS)

    Bydlon, Samuel A.; Dunham, Eric M.

    2015-03-01

    We perform 2-D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman distribution) to study the effects of geometric and material heterogeneity on the rupture process and resulting high-frequency ground motions in the near-fault region (out to ˜20 km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are dominantly controlled by fault roughness. Scattering effects become appreciable beyond ˜3 km from the fault. Near-fault scattering extends the duration of incoherent, high-frequency ground motions and, at least in our 2-D simulations, elevates root-mean-square accelerations (i.e., Arias intensity) with negligible reduction in peak velocities. We also demonstrate that near-fault scattering typically occurs in the power law tail of the power spectral density function, quantified by the Hurst exponent and another parameter combining standard deviation and correlation length.

  1. Seismic hazard analysis. Volume 5. Review panel, Ground Motion Panel, and feedback results

    SciTech Connect

    Bernreuter, D. L.

    1981-08-01

    The Site Specific Spectra Project (SSSP) was a multi-year study funded by the US Nuclear Regulatory Commission to provide estimates of the seismic hazards at a number of nuclear power plant sites in the Eastern US. A key element of our approach was the Peer Review Panel, which we formed in order to ensure that our use of expert opinion was reasonable. We discuss the Peer Review Panel results and provide the complete text of each member's report. In order to improve the ground motion model, an Eastern US Ground Motion Model Panel was formed. In Section 4 we tabulate the responses from the panel members to our feedback questionnaire and discuss the implications of changes introduced by them. We conclude that the net difference in seismic hazard values from those presented in Volume 4 is small and does not warrant a reanalysis. 22 figs.

  2. New models for frequency content prediction of earthquake records based on Iranian ground-motion data

    NASA Astrophysics Data System (ADS)

    Yaghmaei-Sabegh, Saman

    2015-10-01

    This paper presents the development of new and simple empirical models for frequency content prediction of ground-motion records to resolve the assumed limitations on the useable magnitude range of previous studies. Three period values are used in the analysis for describing the frequency content of earthquake ground-motions named as the average spectral period ( T avg), the mean period ( T m), and the smoothed spectral predominant period ( T 0). The proposed models could predict these scalar indicators as function of magnitude, closest site-to-source distance and local site condition. Three site classes as rock, stiff soil, and soft soil has been considered in the analysis. The results of the proposed relationships have been compared with those of other published models. It has been found that the resulting regression equations can be used to predict scalar frequency content estimators over a wide range of magnitudes including magnitudes below 5.5.

  3. Estimating unknown input parameters when implementing the NGA ground-motion prediction equations in engineering practice

    USGS Publications Warehouse

    Kaklamanos, James; Baise, Laurie G.; Boore, David M.

    2011-01-01

    The ground-motion prediction equations (GMPEs) developed as part of the Next Generation Attenuation of Ground Motions (NGA-West) project in 2008 are becoming widely used in seismic hazard analyses. However, these new models are considerably more complicated than previous GMPEs, and they require several more input parameters. When employing the NGA models, users routinely face situations in which some of the required input parameters are unknown. In this paper, we present a framework for estimating the unknown source, path, and site parameters when implementing the NGA models in engineering practice, and we derive geometrically-based equations relating the three distance measures found in the NGA models. Our intent is for the content of this paper not only to make the NGA models more accessible, but also to help with the implementation of other present or future GMPEs.

  4. Observations and stochastic modelling of strong ground motions for the 2011 October 23 Mw 7.1 Van, Turkey, earthquake

    NASA Astrophysics Data System (ADS)

    Akinci, Aybige; Antonioli, Andrea

    2013-03-01

    The 2011 October 23 Van earthquake occurred at 13:41 local time in Eastern Turkey with an epicentre at 43.36oE, 38.76oN (Kandilli Observatory Earthquake Research Institute (KOERI)), 16 km north-northeast of the city of Van, killing around 604 people and leaving thousands homeless. This work presents an overview of the main features of the seismic ground shaking during the Van earthquake. We analyse the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations (SA, 5 per cent of critical damping). In order to understand the characteristics of the ground motions induced by the mainshock, we also study the site response of the strong motion stations that recorded the seismic sequence. The lack of seismic recordings in this area imposes major constraints on the computation of reliable seismic hazard estimates for sites in this part of the country. Towards this aim, we have used a stochastic method to generate high frequency ground motion synthetics for the Mw 7.1 Van 2011 earthquake. The source mechanism of the Van event and regional wave propagation parameters are constrained from the available and previous studies. The selected model parameters are then validated against recordings. We also computed the residuals for the ground motion parameters in terms of PGA and PGV at each station and the model parameter bias by averaging the residuals over all the stations. The attenuation of the simulated ground motion parameters is compared with recent global and regional ground motion prediction equations. Finally, since it has been debated whether the earthquake of November 9 was an aftershock of the October 23 earthquake, we examine whether static variation of Coulomb stress could contribute to the observed aftershock triggering during the 2011 Van Lake sequence. Comparison with empirical ground motion prediction illustrated that the observed PGA data decay faster than the global

  5. A Little Knowledge of Ground Motion: Explaining 3-D Physics-Based Modeling to Engineers

    NASA Astrophysics Data System (ADS)

    Porter, K.

    2014-12-01

    Users of earthquake planning scenarios require the ground-motion map to be credible enough to justify costly planning efforts, but not all ground-motion maps are right for all uses. There are two common ways to create a map of ground motion for a hypothetical earthquake. One approach is to map the median shaking estimated by empirical attenuation relationships. The other uses 3-D physics-based modeling, in which one analyzes a mathematical model of the earth's crust near the fault rupture and calculates the generation and propagation of seismic waves from source to ground surface by first principles. The two approaches produce different-looking maps. The more-familiar median maps smooth out variability and correlation. Using them in a planning scenario can lead to a systematic underestimation of damage and loss, and could leave a community underprepared for realistic shaking. The 3-D maps show variability, including some very high values that can disconcert non-scientists. So when the USGS Science Application for Risk Reduction's (SAFRR) Haywired scenario project selected 3-D maps, it was necessary to explain to scenario users—especially engineers who often use median maps—the differences, advantages, and disadvantages of the two approaches. We used authority, empirical evidence, and theory to support our choice. We prefaced our explanation with SAFRR's policy of using the best available earth science, and cited the credentials of the maps' developers and the reputation of the journal in which they published the maps. We cited recorded examples from past earthquakes of extreme ground motions that are like those in the scenario map. We explained the maps on theoretical grounds as well, explaining well established causes of variability: directivity, basin effects, and source parameters. The largest mapped motions relate to potentially unfamiliar extreme-value theory, so we used analogies to human longevity and the average age of the oldest person in samples of

  6. Characteristics of Earthquake Ground Motion in Tapachula, Chiapas (mexico) from Empirical and Theorical Methods

    NASA Astrophysics Data System (ADS)

    Vidal, F.; Alguacil, G.; Rodríguez, L.; Navarro, M.; Ruiz, A.; Aguirre, J.; Acosta, M.; Gonzalez, R.; Mora, J.; Reyes, M.

    2013-05-01

    The high seismic hazard level of Tapachula city (Chiapas, Mexico) requires a better understanding of the characteristics of earthquake ground motion to implement risk reduction policies in this urban area. A map of ground predominant period estimated with Nakamura technique already shows four different zones: the largest one in the downtown with 0.2-0.4s, two small zones (concentric to the previous one) of 0.4-0.7s and 0.7-0.9 s, respectively, and the smallest zone (on the edge of the city) with the higher values 0.9-1.1s. During 44 days more than 220 events were recorded by a temporal seismic network installed by the UNAM at 6 sites distributed in Tapachula. The magnitude Mw and hypocentral distance of the events were reassessed and range from 3.3 to 4.5 and 60 to 190 km, respectively. After selecting the accelerograms with the best signal/noise ratio, a set of key engineering ground-motion parameters such as peak values of strong motion, acceleration and velocity response spectra, Arias intensity, cumulative absolute velocity, relative significant duration, the Housner spectrum-intensity, the energy input spectrum and H/V spectral ratio were calculated for the selected events. The ground-motion prediction equations (GMPE) of each parameter as function of magnitude and distance were also estimated. On the other hand, synthetic seismic traces were obtained at each station site after modeling a seismic source of magnitude 7.2 by using the empirical Green's function method. Thus, a shake-map scenario was generated for an earthquake similar to that of the September 10, 1993. The parameters here obtained show different shake levels and frequency content at each site. All sites present amplification for 0.25 and 0.5 s. TACA, TAPP y TATC stations, located near the two rivers bordering Tapachula, are those with the largest ground amplification. The characteristics of strong ground motion obtained from synthetic accelerograms are in agreement with those from the empirical

  7. Modifications to existing ground-motion prediction equations in light of new data

    USGS Publications Warehouse

    Atkinson, G.M.; Boore, D.M.

    2011-01-01

    We compare our recent ground-motion prediction equations (GMPEs) for western North America (WNA; Boore and Atkinson, 2008 [BA08]) and eastern North America (ENA; Atkinson and Boore, 2006 [AB06]; Atkinson, 2008 [A08]) to newly available ground-motion data. Based on these comparisons, we suggest revisions to our GMPEs for both WNA and ENA. The revisions for WNA affect only those events with M ??? 5.75, while those for ENA affect all magnitudes. These are simple modifications to the existing GMPEs that bring them into significantly better agreement with data. The wealth of new data clearly demonstrates that these modifications are warranted; we therefore recommend the use of the updated equations for seismic hazard analyses and other applications. More detailed studies are under way by many investigators (including ourselves) to develop a new generation of ground-motion models in both WNA and ENA from scratch, through a comprehensive reevaluation of source, path, site, and modeling issues. In time, those more complete models will replace those proposed in this study. However, as the new models will be several years in development, we recommend using the modified models proposed herein, labeled BA08??? (for WNA), AB06??? (for ENA), and A08??? (for ENA, to replace A08), as interim updates to our existing models. The proposed models are in demonstrable agreement with a rich database of ground motions for moderate-magnitude earthquakes in both WNA and ENA and are constrained at larger magnitudes by the BA08 magnitude and distance scaling.

  8. Real-time modeling of transverse emittance growth due to ground motion

    SciTech Connect

    Shiltsev, V.D.; Parkhomchuk, V.V. |

    1993-09-01

    Ground motion noise at frequencies around 1 kHz causes growth of transverse emittance of the Superconducting Super Collider (SSC) collider beams. The effect was quantitatively investigated using real-time signals from seismometers installed at the tunnel depth and on the surface. The SSC beam was modeled as an ensemble of oscillators with a spread of betatron frequencies. The effect of transverse feedback on emittance growth was investigated.

  9. Basin-related effects on ground motion for earthquake scenarios in the Lower Rhine Embayment

    NASA Astrophysics Data System (ADS)

    Ewald, Michael; Igel, Heiner; Hinzen, Klaus-Günter; Scherbaum, Frank

    2006-07-01

    The deterministic calculation of earthquake scenarios using complete waveform modelling plays an increasingly important role in estimating shaking hazard in seismically active regions. Here we apply 3-D numerical modelling of seismic wave propagation to M 6+ earthquake scenarios in the area of the Lower Rhine Embayment, one of the seismically most active regions in central Europe. Using a 3-D basin model derived from geology, borehole information and seismic experiments, we aim at demonstrating the strong dependence of ground shaking on hypocentre location and basin structure. The simulations are carried out up to frequencies of ca. 1 Hz. As expected, the basin structure leads to strong lateral variations in peak ground motion, amplification and shaking duration. Depending on source-basin-receiver geometry, the effects correlate with basin depth and the slope of the basin flanks; yet, the basin also affects peak ground motion and estimated shaking hazard thereof outside the basin. Comparison with measured seismograms for one of the earthquakes shows that some of the main characteristics of the wave motion are reproduced. Cumulating the derived seismic intensities from the three modelled earthquake scenarios leads to a predominantly basin correlated intensity distribution for our study area.

  10. Ground motion simulations in Marmara (Turkey) region from 3D finite difference method

    NASA Astrophysics Data System (ADS)

    Aochi, Hideo; Ulrich, Thomas; Douglas, John

    2016-04-01

    In the framework of the European project MARSite (2012-2016), one of the main contributions from our research team was to provide ground-motion simulations for the Marmara region from various earthquake source scenarios. We adopted a 3D finite difference code, taking into account the 3D structure around the Sea of Marmara (including the bathymetry) and the sea layer. We simulated two moderate earthquakes (about Mw4.5) and found that the 3D structure improves significantly the waveforms compared to the 1D layer model. Simulations were carried out for different earthquakes (moderate point sources and large finite sources) in order to provide shake maps (Aochi and Ulrich, BSSA, 2015), to study the variability of ground-motion parameters (Douglas & Aochi, BSSA, 2016) as well as to provide synthetic seismograms for the blind inversion tests (Diao et al., GJI, 2016). The results are also planned to be integrated in broadband ground-motion simulations, tsunamis generation and simulations of triggered landslides (in progress by different partners). The simulations are freely shared among the partners via the internet and the visualization of the results is diffused on the project's homepage. All these simulations should be seen as a reference for this region, as they are based on the latest knowledge that obtained during the MARSite project, although their refinement and validation of the model parameters and the simulations are a continuing research task relying on continuing observations. The numerical code used, the models and the simulations are available on demand.

  11. Guidelines for earthquake ground motion definition for the eastern United States

    SciTech Connect

    Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

    1985-01-01

    Guidelines for the determination of earthquake ground-motion definition for the eastern United States are established in this paper. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large to great (M > 7.5) sized earthquakes have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes have been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data has been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the Safe Shutdown Earthquake, SSE. A new procedure for establishing the Operating Basis Earthquake, OBE, is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., 2 figs., 1 tab.

  12. Mean and modal ϵ in the deaggregation of probabilistic ground motion

    USGS Publications Warehouse

    Harmsen, Stephen C.

    2001-01-01

    Mean and modal ϵ exhibit a wide variation geographically for any specified PE. Modal ϵ for the 2% in 50 yr PE exceeds 2 near the most active western California faults, is less than –1 near some less active faults of the western United States (principally in the Basin and Range), and may be less than 0 in areal fault zones of the central and eastern United States (CEUS). This geographic variation is useful for comparing probabilistic ground motions with ground motions from scenario earthquakes on dominating faults, often used in seismic-resistant provisions of building codes. An interactive seismic-hazard deaggregation menu item has been added to the USGS probabilistic seismic-hazard analysis Web site, http://geohazards.cr.usgs.gov/eq/, allowing visitors to compute mean and modal distance, magnitude, and ϵ corresponding to ground motions having mean return times from 250 to 5000 yr for any site in the United States.

  13. Ground Motion Prediction of Subduction Earthquakes using the Onshore-Offshore Ambient Seismic Field

    NASA Astrophysics Data System (ADS)

    Viens, L.; Miyake, H.; Koketsu, K.

    2014-12-01

    Seismic waves produced by earthquakes already caused plenty of damages all around the world and are still a real threat to human beings. To reduce seismic risk associated with future earthquakes, accurate ground motion predictions are required, especially for cities located atop sedimentary basins that can trap and amplify these seismic waves. We focus this study on long-period ground motions produced by subduction earthquakes in Japan which have the potential to damage large-scale structures, such as high-rise buildings, bridges, and oil storage tanks. We extracted the impulse response functions from the ambient seismic field recorded by two stations using one as a virtual source, without any preprocessing. This method allows to recover the reliable phases and relative, rather than absolute, amplitudes. To retrieve corresponding Green's functions, the impulse response amplitudes need to be calibrated using observational records of an earthquake which happened close to the virtual source. We show that Green's functions can be extracted between offshore submarine cable-based sea-bottom seismographic observation systems deployed by JMA located atop subduction zones and on-land NIED/Hi-net stations. In contrast with physics-based simulations, this approach has the great advantage to predict ground motions of moderate earthquakes (Mw ~5) at long-periods in highly populated sedimentary basin without the need of any external information about the velocity structure.

  14. Structure-specific scalar intensity measures for near-source and ordinary earthquake ground motions

    USGS Publications Warehouse

    Luco, N.; Cornell, C.A.

    2007-01-01

    Introduced in this paper are several alternative ground-motion intensity measures (IMs) that are intended for use in assessing the seismic performance of a structure at a site susceptible to near-source and/or ordinary ground motions. A comparison of such IMs is facilitated by defining the "efficiency" and "sufficiency" of an IM, both of which are criteria necessary for ensuring the accuracy of the structural performance assessment. The efficiency and sufficiency of each alternative IM, which are quantified via (i) nonlinear dynamic analyses of the structure under a suite of earthquake records and (ii) linear regression analysis, are demonstrated for the drift response of three different moderate- to long-period buildings subjected to suites of ordinary and of near-source earthquake records. One of the alternative IMs in particular is found to be relatively efficient and sufficient for the range of buildings considered and for both the near-source and ordinary ground motions. ?? 2007, Earthquake Engineering Research Institute.

  15. The effects of the topographic bench on ground motion from mining explosions

    SciTech Connect

    Bonner, J.L.; Blomberg, W.S.; Hopper, H.; Leidig, M.

    2005-07-01

    Understanding the effects of the bench on ground motion can improve the design of cast blasts and achieve improved blast efficiency while remaining below vibration requirements. A new dataset recorded in September 2003 from a coal mine in Arizona has allowed us to examine the excitation of short-period Rayleigh-type surface waves from four simultaneously-detonated explosions in and below a topographic bench of a mine. The explosions were recorded on a network of over 150 seismic sensors, providing an extensive understanding of the ground motion radiation patterns from these explosions. We detonated two separate explosions in the deepest pit of the mine, thus the explosions were shot to solid rock. Within 25 meters of these two explosions, we detonated two additional explosions of similar explosive yields in a bench, thus these explosions were shot to the free face. Radiation patterns and spectral ratios from the explosions show increased amplitudes at azimuths behind the bench relative to the amplitudes in front of the bench. We compared these findings to seismic observations from two {approximately} 1.5 million pound cast blasts at the same mine and found similar radiations patterns. Modeling of these blasts shows that the variations in ground motion are caused by the topographic bench as a result of 1) horizontal spalling of the rock falling into the pit and 2) non-linear scattering near the free-face. Shooting to a buffer also causes the azimuthal variations to be significantly reduced.

  16. A short note on ground-motion recordings from the M 7.9 Wenchuan, China, earthquake and ground-motion prediction equations in the Central and Eastern United States

    USGS Publications Warehouse

    Wang, Z.; Lu, M.

    2011-01-01

    The 12 May 2008 Wenchuan earthquake (M 7.9) occurred along the western edge of the eastern China SCR and was well recorded by modern strong-motion instruments: 93 strong-motion stations within 1.4 to 300 km rupture distance recorded the main event. Preliminary comparisons show some similarities between ground-motion attenuation in the Wenchuan region and the central and eastern United States, suggesting that ground motions from the Wenchuan earthquake could be used as a database providing constraints for developing GMPEs for large earthquakes in the central and eastern United States.

  17. On the generation of tangential ground motion by underground explosions in jointed rocks

    NASA Astrophysics Data System (ADS)

    Vorobiev, Oleg; Ezzedine, Souheil; Antoun, Tarabay; Glenn, Lewis

    2015-03-01

    This paper describes computational studies of tangential ground motions generated by spherical explosions in a heavily jointed granite formation. Various factors affecting the shear wave generation are considered, including joint spacing, orientation and frictional properties. Simulations are performed both in 2-D for a single joint set to elucidate the basic response mechanisms, and in 3-D for multiple joint sets to realistically represent in situ conditions in a realistic geological setting. The joints are modelled explicitly using both contact elements and weakness planes in the material. Simulations are performed both deterministically and stochastically to quantify the effects of geological uncertainties on near field ground motions. The mechanical properties of the rock and the joints as well as the joint spacing and orientation are taken from experimental test data and geophysical logs corresponding to the Climax Stock granitic outcrop, which is the geological setting of the source physics experiment (SPE). Agreement between simulation results and near field wave motion data from SPE enables newfound understanding of the origin and extent of non-spherical motions associated with underground explosions in fractured geological media.

  18. Correlation of ground motion and intensity for the 17 January 1994 Northridge, California, earthquake

    USGS Publications Warehouse

    Boatwright, J.; Thywissen, K.; Seekins, L.C.

    2001-01-01

    We analyze the correlations between intensity and a set of groundmotion parameters obtained from 66 free-field stations in Los Angeles County that recorded the 1994 Northridge earthquake. We use the tagging intensities from Thywissen and Boatwright (1998) because these intensities are determined independently on census tracts, rather than interpolated from zip codes, as are the modified Mercalli isoseismals from Dewey et al. (1995). The ground-motion parameters we consider are the peak ground acceleration (PGA), the peak ground velocity (PGV), the 5% damped pseudovelocity response spectral (PSV) ordinates at 14 periods from 0.1 to 7.5 sec, and the rms average of these spectral ordinates from 0.3 to 3 sec. Visual comparisons of the distribution of tagging intensity with contours of PGA, PGV, and the average PSV suggest that PGV and the average PSV are better correlated with the intensity than PGA. The correlation coefficients between the intensity and the ground-motion parameters bear this out: r = 0.75 for PGA, 0.85 for PGV, and 0.85 for the average PSV. Correlations between the intensity and the PSV ordinates, as a function of period, are strongest at 1.5 sec (r = 0.83) and weakest at 0.2 sec (r = 0.66). Regressing the intensity on the logarithms of these ground-motion parameters yields relations I ?? mlog?? with 3.0 ??? m ??? 5.2 for the parameters analyzed, where m = 4.4 ?? 0.7 for PGA, 3.4 ?? 0.4 for PGV, and 3.6 ?? 0.5 for the average PSV.

  19. Strong ground motions of the 2009 L'Aquila earthquake: modeling and scenario simulations

    NASA Astrophysics Data System (ADS)

    Gallovič, F.; Ameri, G.; Pacor, F.

    2012-04-01

    On April 6, 2009 a Mw 6.3 earthquake struck the L'Aquila city, one of the largest urban centers in the Abruzzo region (Central Italy), causing a large number of casualties and damage in the town and surrounding villages. The earthquake has been recorded by several digital stations of the Italian Strong-Motion Network. The collected records represent a unique dataset in Italy in terms of number and quality of records, azimuthal coverage and presence of near-fault recordings. Soon after the earthquake the damage in the epicentral area was also assessed providing macroseismic intensity estimates, in MCS scale, for 314 localities (I ≥5). Despite the moderate magnitude of the L'Aquila earthquake, the strong-motion and macroseismic data in the vicinity of the fault depict a large variability of the observed shaking and damage. In this study we present broadband (0.1 - 10 Hz) ground motion simulations of the 2009 L'Aquila earthquake to be used for engineering purposes in the region. We utilize Hybrid Integral-Composite (HIC, Gallovič and Brokešová, 2007) approach based on a k-square kinematic rupture model, combining low-frequency coherent and high-frequency incoherent source radiation and providing omega-squared source spectral decay. We first model the recorded seismograms in order to calibrate source parameters and to assess the capabilities of the broadband simulation model. To this end, position and slip amount of the two main asperities, the largest asperity time delay and the rupture velocity distribution on the fault is constrained, based on the low-frequency slip inversion result. Synthetic Green's functions are calculated in a 1D-layered crustal model including 1D soil profiles to account for site-specific response (where available). The goodness-of-fit is evaluated in time (peak values and duration) and frequency domains (elastic and inelastic response spectra) and shows a remarkable agreement between observed and simulated data at most of the stations

  20. Displacement response analysis of base-isolated buildings subjected to near-fault ground motions with velocity pulse

    NASA Astrophysics Data System (ADS)

    He, Qiumei; Li, Xiaojun; Yang, Yu; Liu, Aiwen; Li, Yaqi

    2016-04-01

    In order to study the influence of the velocity pulse to seismic displacement response of base-isolated buildings and the differences of the influent of the two types of near-fault ground motions with velocity pulse to seismic response of base-isolated buildings, the seismic responses are analyzed by three dimensional finite element models for three base-isolated buildings, 4 stories, 9 stories and 14 stories. In this study, comparative analyses were done for the seismic displacement responses of the base-isolated structures under 6 near-fault ground motion records with velocity pulse and no velocity pulse, in which, 6 artificial ground motion time histories with same elastic response spectrum as the 6 near-fault ground motion records are used as the ground motion with no velocity pulse. This study indicates that under the ground motions with velocity pulse the seismic displacement response of base-isolated buildings is significantly increased than the ground motions with no velocity pulse. To the median-low base-isolated buildings, the impact of forward directivity pulses is bigger than fling-step pulses. To the high base-isolated buildings, the impact of fling-step pulses is bigger than forward directivity pulses. The fling-step pulses lead to large displacement response in the lower stories. This work has been supported by the National Natural Science Foundation of China (Grant No.51408560)

  1. Probabilistic seismic hazard analyses for ground motions and fault displacement at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Stepp, J.C.; Wong, I.; Whitney, J.; Quittmeyer, R.; Abrahamson, N.; Toro, G.; Young, S.R.; Coppersmith, K.; Savy, J.; Sullivan, T.

    2001-01-01

    Probabilistic seismic hazard analyses were conducted to estimate both ground motion and fault displacement hazards at the potential geologic repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. The study is believed to be the largest and most comprehensive analyses ever conducted for ground-shaking hazard and is a first-of-a-kind assessment of probabilistic fault displacement hazard. The major emphasis of the study was on the quantification of epistemic uncertainty. Six teams of three experts performed seismic source and fault displacement evaluations, and seven individual experts provided ground motion evaluations. State-of-the-practice expert elicitation processes involving structured workshops, consensus identification of parameters and issues to be evaluated, common sharing of data and information, and open exchanges about the basis for preliminary interpretations were implemented. Ground-shaking hazard was computed for a hypothetical rock outcrop at -300 m, the depth of the potential waste emplacement drifts, at the designated design annual exceedance probabilities of 10-3 and 10-4. The fault displacement hazard was calculated at the design annual exceedance probabilities of 10-4 and 10-5.

  2. Long Period Ground Motion at Bedrock Level in Delhi City from Himalayan Earthquake Scenarios

    NASA Astrophysics Data System (ADS)

    Parvez, Imtiyaz A.; Romanelli, Fabio; Panza, Giuliano F.

    2011-03-01

    Delhi, the capital of India, is prone to severe seismic hazards, not only from local events but also from Himalayan earthquakes at distances of 250-300 km. Standard techniques are not sufficiently reliable to completely characterize the seismic hazards in this case due to the difficulty of predicting the occurrence of earthquakes (frequency-magnitude relations) and of properly treating the propagation of their effects (attenuation laws), especially their long-period components. In order to give a sound description of the seismic ground motion due to an earthquake in such a given range of distances (and magnitudes), we use modelling techniques developed from physics of the seismic source generation and propagation processes. Such models take into account the directivity effect of rupture propagation and the attenuation of (long-period) ground motions. The generated ground motion scenarios permit us to build a very important knowledge base to be fruitfully used by civil engineers, since long period ground motions, especially if amplified by deep sedimentary basins, can represent a severe threat for large scale structures (e.g. lifelines and bridges) and tall buildings, which are widespread in fast-growing megacities. In this study, we simulate the ground motion, at bedrock level, in Delhi city, for an earthquake scenario corresponding to a source of Mw = 8.0 located in the central seismic gap of Himalayas, at an epicentral distance of about 300 km from Delhi city. By means of several parametric studies, we simulate the time histories using Size Scaled Point Source, Space and Time Scaled Point Source and Extended Source models. Together with the complete time histories (displacements, velocities and accelerations, from which the peak amplitudes have been extracted), we have also used the displacement response spectrum to characterize the seismic input at Delhi. Not only is the displacement response spectrum of great significance to modern displacement-based design

  3. Influence Of Site Classification On Computing Empirical Ground-Motion Prediction Equations In Italy

    NASA Astrophysics Data System (ADS)

    di Alessandro, C.; Bonilla, L.; Rovelli, A.; Scotti, O.

    2008-12-01

    In this study, we investigate a site classification method for stations of the Italian Accelerometric Network based on the predominant period of ground motion at the site. The site predominant period is identified from the average horizontal-to-vertical (H/V) spectral ratios of the 5%-damped response spectra of Italian earthquake records. We selected a data-set of 610 three-component analogue and digital recordings from 120 earthquakes recorded at 214 seismic stations within an hypocentral distance of 200 km. Selected events are in the moment-magnitude Mw range of 4.0 to 6.8 and the focal depth ranges from 5 to 40 km. Whenever possible, we classified each site by assigning them to one of six predominant period classes (in the range 0.05 to 2 seconds) that we propose as a modification of the Zhao et al. (2006) procedure. We then investigated the impact of this classification scheme on empirical ground-motion prediction equations. We adopted the same functional form of Fukushima et al. (2007) and we computed a nonlinear period- dependent regression that allowed us to derive site coefficients using the proposed six predominant period classes. We also derived site coefficients for a simplified classification based on the general soil conditions at each site. This classification uses two classes (which we call A-B and C-D, with Vs ≥ 360 m/s and Vs < 360 m/s, respectively) based on the four basic ground categories in the current European (CEN 2004) and Italian seismic codes. Our empirical site classification scheme based on strong-motion data provides the opportunity to explore whether we can decrease the misfit by improving the site characterization of the Italian data set. Comparison of our results with other empirical ground-motion prediction equations (GMPEs) based on conventional site classifications do not display a significant reduction of overall standard deviation. However, our site classification schemes shows promise in reducing the uncertainty in ground-motion

  4. Approach to developing a ground-motion design basis for facilities important to safety at Yucca Mountain

    SciTech Connect

    King, J.L.

    1990-04-01

    The Department of Energy has proposed a methodology for developing a ground-motion design basis for prospective facilities at Yucca Mountain that are important to safety. The methodology utilizes a quasi-deterministic construct that is designed to provide a conservative, robust, and reproducible estimate of ground motion that has a one-in-ten chance of occurring during the preclosure period. This estimate is intended to define a ground-motion level for which the seismic design would ensure minimal disruption to operations; engineering analyses to ensure safe performance in the unlikely event that the design basis is exceeded are a part of the proposed methodology. 8 refs.

  5. A study of possible ground-motion amplification at the Coyote Lake Dam, California

    USGS Publications Warehouse

    Boore, D.M.; Graizer, V.M.; Tinsley, J.C.; Shakal, A.F.

    2004-01-01

    The abutment site at the Coyote Lake Dam recorded an unusually large peak acceleration of 1.29g during the 1984 Morgan Hill earthquake. Following this earthquake another strong-motion station was installed about 700 m downstream from the abutment station. We study all events (seven) recorded on these stations, using ratios of peak accelerations, spectral ratios, and particle motion polarization (using holograms) to investigate the relative ground motion at the two sites. We find that in all but one case the motion at the abutment site is larger than the downstream site over a broad frequency band. The polarizations are similar for the two sites for a given event, but can vary from one event to another. This suggests that the dam itself is not strongly influencing the records. Although we can be sure that the relative motion is usually larger at the abutment site, we cannot conclude that there is anomalous site amplification at the abutment site. The downstream site could have lower-than-usual near-surface amplifications. On the other hand, the geology near the abutment site is extremely complex and includes fault slivers, with rapid lateral changes in materials and presumably seismic velocities. For this reason alone, the abutment site should not be considered a normal free-field site.

  6. Fast Computation of Ground Motion Shaking Map base on the Modified Stochastic Finite Fault Modeling

    NASA Astrophysics Data System (ADS)

    Shen, W.; Zhong, Q.; Shi, B.

    2012-12-01

    Rapidly regional MMI mapping soon after a moderate-large earthquake is crucial to loss estimation, emergency services and planning of emergency action by the government. In fact, many countries show different degrees of attention on the technology of rapid estimation of MMI , and this technology has made significant progress in earthquake-prone countries. In recent years, numerical modeling of strong ground motion has been well developed with the advances of computation technology and earthquake science. The computational simulation of strong ground motion caused by earthquake faulting has become an efficient way to estimate the regional MMI distribution soon after earthquake. In China, due to the lack of strong motion observation in network sparse or even completely missing areas, the development of strong ground motion simulation method has become an important means of quantitative estimation of strong motion intensity. In many of the simulation models, stochastic finite fault model is preferred to rapid MMI estimating for its time-effectiveness and accuracy. In finite fault model, a large fault is divided into N subfaults, and each subfault is considered as a small point source. The ground motions contributed by each subfault are calculated by the stochastic point source method which is developed by Boore, and then summed at the observation point to obtain the ground motion from the entire fault with a proper time delay. Further, Motazedian and Atkinson proposed the concept of Dynamic Corner Frequency, with the new approach, the total radiated energy from the fault and the total seismic moment are conserved independent of subfault size over a wide range of subfault sizes. In current study, the program EXSIM developed by Motazedian and Atkinson has been modified for local or regional computations of strong motion parameters such as PGA, PGV and PGD, which are essential for MMI estimating. To make the results more reasonable, we consider the impact of V30 for the

  7. Ground motion in Anchorage, Alaska, from the 2002 Denali fault earthquake: Site response and Displacement Pulses

    USGS Publications Warehouse

    Boore, D.M.

    2004-01-01

    Data from the 2002 Denali fault earthquake recorded at 26 sites in and near Anchorage, Alaska, show a number of systematic features important in studies of site response and in constructing long-period spectra for use in earthquake engineering. The data demonstrate that National Earthquake Hazards Reduction Program (NEHRP) site classes are a useful way of grouping stations according to site amplification. In general, the sites underlain by lower shear-wave velocities have higher amplification. The amplification on NEHRP class D sites exceeds a factor of 2 relative to an average of motions on class C sites. The amplifications are period dependent. They are in rough agreement with those from previous studies, but the new data show that the amplifications extend to at least 10 sec, periods longer than considered in previous studies. At periods longer than about 14 sec, all sites have motion of similar amplitude, and the ground displacements are similar in shape, polarization, and amplitude for all stations. The displacement ground motion is dominated by a series of four pulses, which are associated with the three subevents identified in inversion studies (the first pulse is composed of P waves from the first subevent). Most of the high-frequency ground motion is associated with the S waves from subevent 1. The pulses from subevents 1 and 2, with moment releases corresponding to M 7.1 and 7.0, are similar to the pulse of displacement radiated by the M 7.1 Hector Mine earthquake. The signature from the largest subevent (M 7.6) is more subdued than those from the first two subevents. The two largest pulses produce response spectra with peaks at a period of about 15 sec. The spectral shape at long periods is in good agreement with the recent 2003 NEHRP code spectra but is in poor agreement with the shape obtained from Eurocode 8.

  8. By How Much Can Physics-Based Earthquake Simulations Reduce the Uncertainties in Ground Motion Predictions?

    NASA Astrophysics Data System (ADS)

    Jordan, T. H.; Wang, F.

    2014-12-01

    Probabilistic seismic hazard analysis (PSHA) is the scientific basis for many engineering and social applications: performance-based design, seismic retrofitting, resilience engineering, insurance-rate setting, disaster preparation, emergency response, and public education. The uncertainties in PSHA predictions can be expressed as an aleatory variability that describes the randomness of the earthquake system, conditional on a system representation, and an epistemic uncertainty that characterizes errors in the system representation. Standard PSHA models use empirical ground motion prediction equations (GMPEs) that have a high aleatory variability, primarily because they do not account for the effects of crustal heterogeneities, which scatter seismic wavefields and cause local amplifications in strong ground motions that can exceed an order of magnitude. We show how much this variance can be lowered by simulating seismic wave propagation through 3D crustal models derived from waveform tomography. Our basic analysis tool is the new technique of averaging-based factorization (ABF), which uses a well-specified seismological hierarchy to decompose exactly and uniquely the logarithmic excitation functional into a series of uncorrelated terms that include unbiased averages of the site, path, hypocenter, and source-complexity effects (Feng & Jordan, Bull. Seismol. Soc. Am., 2014, doi:10.1785/0120130263). We apply ABF to characterize the differences in ground motion predictions between the standard GMPEs employed by the National Seismic Hazard Maps and the simulation-based CyberShake hazard model of the Southern California Earthquake Center. The ABF analysis indicates that, at low seismic frequencies (< 1 Hz), CyberShake site and path effects unexplained by the GMPEs account 40-50% of total residual variance. Therefore, accurate earthquake simulations have the potential for reducing the aleatory variance of the strong-motion predictions by about a factor of two, which would

  9. Ground motion modelling in the Gujarat region of Western India using empirical Green's function approach

    NASA Astrophysics Data System (ADS)

    Choudhury, Pallabee; Chopra, Sumer; Roy, Ketan Singha; Sharma, Jyoti

    2016-04-01

    In this study, ground motions are estimated for scenario earthquakes of Mw 6.0, 6.5 and 7.0 at 17 sites in Gujarat region using Empirical Green's function technique. The Dholavira earthquake of June 19, 2012 (Mw 5.1) which occurred in the Kachchh region of Gujarat is considered as an element earthquake. We estimated the focal mechanism and source parameters of the element earthquake using standard methodologies. The moment tensor inversion technique is used to determine the fault plane solution (strike = 8°, dip = 51°, and rake = - 7°). The seismic moment and the stress drop are 5.6 × 1016 Nm and 120 bars respectively. The validity of the approach was tested for a smaller earthquake. A few possible directivity scenarios were also tested to find out the effect of directivity on the level of ground motions. Our study reveals that source complexities and site effects play a very important role in deciding the level of ground motions at a site which are difficult to model by GMPEs. Our results shed new light on the expected accelerations in the region and suggest that the Kachchh region can expect maximum acceleration of around 500 cm/s2 at few sites near source and around 200 cm/s2 at most of the sites located within 50 km from the epicentre for a Mw 7.0 earthquake. The estimated ground accelerations can be used by the administrators and planners for providing a guiding framework to undertake mitigation investments and activities in the region.

  10. Simulation of strong ground motion in northern Iran using the specific barrier model

    NASA Astrophysics Data System (ADS)

    Soghrat, M. R.; Khaji, N.; Zafarani, H.

    2012-02-01

    In this study, based upon the calibrated specific barrier model (SBM) against the latest available strong motion data, ground motion prediction equations for soil and rock sites in northern Iran are developed. The SBM may provide the most complete, simple and self-consistent description of the faulting process, which is applicable in both 'near-fault' and 'far-field' regions. Consequently, the SBM may provide consistent ground motion simulations over the entire necessary frequency range and for all distances of engineering interests. To determine source parameters in this study, we used 163 three-component records of 32 earthquakes with magnitude ranging from MW 4.9 to 7.4 in northern Iran. In the database, records with hypocentral distances less than 200 km are chosen and only earthquakes whose moment-magnitude estimates are available have been used. Furthermore, using the best available information, recording sites are classified into two main geologic categories: rock and soil. Because of the lack of site amplification information in the most regions of the world including Iran, we used the H/V ratio method for estimating the site amplification. Moreover, the Kappa factor that shows diminishing the high-frequency amplitude is determined. In this study, two data sets are considered for determining the source parameters (ΔσG and ΔσL) and the H/V ratio and the Kappa factor. Only S-wave part of signals is used in each analysis. Regression analysis is performed using 'random effects' method that considers both interseismic (event-to-event) and coseismic (within-event) variabilities to effectively deal with the problem of weighting observations from different earthquakes. The residuals are controlled against available northern Iranian strong ground motion data to verify that the model predictions are unbiased and that there are no significant residual trends with magnitude and distance. At first, it is assumed that no sign of self-similarity breakdown is observed

  11. Strong ground motion in the Taipei basin from the 1999 Chi-Chi, Taiwan, earthquake

    USGS Publications Warehouse

    Fletcher, Joe B.; Wen, K.-L.

    2005-01-01

    The Taipei basin, located in northwest Taiwan about 160 km from the epicenter of the Chi-Chi earthquake, is a shallow, triangular-shaped basin filled with low-velocity fluvial deposits. There is a strong velocity contrast across the basement interface of about 600 m/sec at a depth of about 600-700 m in the deeper section of the basin, suggesting that ground motion should be amplified at sites in the basin. In this article, the ground-motion recordings are analyzed to determine the effect of the basin both in terms of amplifications expected from a 1D model of the sediments in the basin and in terms of the 3D structure of the basin. Residuals determined for peak acceleration from attenuation curves are more positive (amplified) in the basin (average of 5.3 cm/ sec2 compared to - 24.2 cm/sec2 for those stations outside the basin and between 75 and 110 km from the surface projection of the faulted area, a 40% increase in peak ground acceleration). Residuals for peak velocity are also significantly more positive at stations in the basin (31.8 cm/sec compared to 20.0 cm/sec out). The correlation of peak motion with depth to basement, while minor in peak acceleration, is stronger in the peak velocities. Record sections of ground motion from stations in and around the Taipei basin show that the largest long-period arrival, which is coherent across the region, is strongest on the vertical component and has a period of about 10-12 sec. This phase appears to be a Rayleigh wave, probably associated with rupture at the north end of the Chelungpu fault. Records of strong motion from stations in and near the basin have an additional, higher frequency signal: nearest the deepest point in the basin, the signal is characterized by frequencies of about 0.3 - 0.4 Hz. These frequencies are close to simple predictions using horizontal layers and the velocity structure of the basin. Polarizations of the S wave are mostly coherent across the array, although there are significant

  12. Enhancement of long period components of recorded and synthetic ground motions using InSAR

    USGS Publications Warehouse

    Abell, J.A.; Carlos de la Llera, J.; Wicks, C.W.

    2011-01-01

    Tall buildings and flexible structures require a better characterization of long period ground motion spectra than the one provided by current seismic building codes. Motivated by that, a methodology is proposed and tested to improve recorded and synthetic ground motions which are consistent with the observed co-seismic displacement field obtained from interferometric synthetic aperture radar (InSAR) analysis of image data for the Tocopilla 2007 earthquake (Mw=7.7) in Northern Chile. A methodology is proposed to correct the observed motions such that, after double integration, they are coherent with the local value of the residual displacement. Synthetic records are generated by using a stochastic finite-fault model coupled with a long period pulse to capture the long period fling effect. It is observed that the proposed co-seismic correction yields records with more accurate long-period spectral components as compared with regular correction schemes such as acausal filtering. These signals provide an estimate for the velocity and displacement spectra, which are essential for tall-building design. Furthermore, hints are provided as to the shape of long-period spectra for seismic zones prone to large co-seismic displacements such as the Nazca-South American zone. ?? 2011 Elsevier Ltd.

  13. Repeatable path effect on ground-motion variability at a single station from Taiwan

    NASA Astrophysics Data System (ADS)

    Sung, Chih-Hsuan; Lee, Chyi-Tyi

    2016-04-01

    This paper presents the path component of error can be directly evaluated from the ground-motion estimates for future earthquake events by the new approach, Path Diagram. We use 150 shallow earthquakes (about 19,887 records) which moment magnitudes are greater than 4.0 from the Taiwan Strong-Motion Instrumentation Program network to set up the Taiwan Ground-motion prediction equations for PGA and SA. The intra-record residuals are divided into small brackets of rose diagram for four station-to-event distance bins and eight station-to-event azimuth bins to estimate the mean residuals for each path bin; hence, we can obtain a repeatable path-term and aleatory residuals for each station. Results show that this new method can catch more path effect than semi-variogram and closeness index (CI) methods, it means, if we use this approach to separate the record-to-record variability, the minimum remaining unexplained intra-event variability will get. Finally, we use the distribution map of path-to-path sigma for each station to analyze different regions in Taiwan.

  14. Spatial variation of earthquake ground motion for application to soil-structure interaction

    SciTech Connect

    Abrahamson, N. )

    1992-03-01

    The spatial variation of strong ground motion from fifteen earthquakes recorded by the Lotung LSST strong motion array is analyzed. The earthquakes range in magnitude from 3.7 to 7.8 and in source distance from 4 to 80 km. In all a total of 533 station pairs are used with station separations ranging from 60 to 85 meters. The spatial variation of ground motion is divided into two parts: variation in the fourier phase (coherence), and variation in the Fourier amplitude. Empirical functions describing the frequency and separation distance dependence of the coherency and amplitude variation appropriate for use in engineering analyses are derived. Taken together, the spatial variation functions given in this study provide a complete description of the statistical properties of the horizontal components of the seismic wavefield assuming plane wave propagation for the S-wave window. Since the S-waves generally cause the largest shaking, these spatial variation functions are appropriate for use in engineering analyses of large structures.

  15. Spatial variation of earthquake ground motion for application to soil-structure interaction. Final report

    SciTech Connect

    Abrahamson, N.

    1992-03-01

    The spatial variation of strong ground motion from fifteen earthquakes recorded by the Lotung LSST strong motion array is analyzed. The earthquakes range in magnitude from 3.7 to 7.8 and in source distance from 4 to 80 km. In all a total of 533 station pairs are used with station separations ranging from 60 to 85 meters. The spatial variation of ground motion is divided into two parts: variation in the fourier phase (coherence), and variation in the Fourier amplitude. Empirical functions describing the frequency and separation distance dependence of the coherency and amplitude variation appropriate for use in engineering analyses are derived. Taken together, the spatial variation functions given in this study provide a complete description of the statistical properties of the horizontal components of the seismic wavefield assuming plane wave propagation for the S-wave window. Since the S-waves generally cause the largest shaking, these spatial variation functions are appropriate for use in engineering analyses of large structures.

  16. Measurement of six degree-of-freedom ground motion by using eight accelerometers

    NASA Astrophysics Data System (ADS)

    Yang, Zhenyu; Shen, Yi; Liu, Zhiyan

    2005-12-01

    A new integrated measuring system with eight force-balance accelerometers is proposed to obtain a direct measurement of six degree-of freedom (DOF) ground motions, including three rotational and three actual translational acceleration components without gyroscopes. In the proposed measuring system, the relationship between the output from eight force-balance accelerometer and the six DOF motion of the measuring system under an earthquake are described by differential equations. These equations are derived from the positions and directions of the eight force-balance accelerometers in the measuring system. The third-order Runge-Kutta algorithm is used to guarantee the accuracy of the numerical calculation. All the algorithms used to compute the six DOF components of the ground motion are implemented in a real-time in Digital Signal Processor (DSP). The distortion of the measured results caused by position and direction errors of the accelerometers in the measuring system are reduced by multiplying a compensation coefficient C to the output and subtracting static zero drift from the measured results, respectively.

  17. Stochastic ground-motion simulation of two Himalayan earthquakes: seismic hazard assessment perspective

    NASA Astrophysics Data System (ADS)

    Harbindu, Ashish; Sharma, Mukat Lal; Kamal

    2012-04-01

    The earthquakes in Uttarkashi (October 20, 1991, M w 6.8) and Chamoli (March 8, 1999, M w 6.4) are among the recent well-documented earthquakes that occurred in the Garhwal region of India and that caused extensive damage as well as loss of life. Using strong-motion data of these two earthquakes, we estimate their source, path, and site parameters. The quality factor ( Q β ) as a function of frequency is derived as Q β ( f) = 140 f 1.018. The site amplification functions are evaluated using the horizontal-to-vertical spectral ratio technique. The ground motions of the Uttarkashi and Chamoli earthquakes are simulated using the stochastic method of Boore (Bull Seismol Soc Am 73:1865-1894, 1983). The estimated source, path, and site parameters are used as input for the simulation. The simulated time histories are generated for a few stations and compared with the observed data. The simulated response spectra at 5% damping are in fair agreement with the observed response spectra for most of the stations over a wide range of frequencies. Residual trends closely match the observed and simulated response spectra. The synthetic data are in rough agreement with the ground-motion attenuation equation available for the Himalayas (Sharma, Bull Seismol Soc Am 98:1063-1069, 1998).

  18. A Bayesian and Physics-Based Ground Motion Parameters Map Generation System

    NASA Astrophysics Data System (ADS)

    Ramirez-Guzman, L.; Quiroz, A.; Sandoval, H.; Perez-Yanez, C.; Ruiz, A. L.; Delgado, R.; Macias, M. A.; Alcántara, L.

    2014-12-01

    We present the Ground Motion Parameters Map Generation (GMPMG) system developed by the Institute of Engineering at the National Autonomous University of Mexico (UNAM). The system delivers estimates of information associated with the social impact of earthquakes, engineering ground motion parameters (gmp), and macroseismic intensity maps. The gmp calculated are peak ground acceleration and velocity (pga and pgv) and response spectral acceleration (SA). The GMPMG relies on real-time data received from strong ground motion stations belonging to UNAM's networks throughout Mexico. Data are gathered via satellite and internet service providers, and managed with the data acquisition software Earthworm. The system is self-contained and can perform all calculations required for estimating gmp and intensity maps due to earthquakes, automatically or manually. An initial data processing, by baseline correcting and removing records containing glitches or low signal-to-noise ratio, is performed. The system then assigns a hypocentral location using first arrivals and a simplified 3D model, followed by a moment tensor inversion, which is performed using a pre-calculated Receiver Green's Tensors (RGT) database for a realistic 3D model of Mexico. A backup system to compute epicentral location and magnitude is in place. A Bayesian Kriging is employed to combine recorded values with grids of computed gmp. The latter are obtained by using appropriate ground motion prediction equations (for pgv, pga and SA with T=0.3, 0.5, 1 and 1.5 s ) and numerical simulations performed in real time, using the aforementioned RGT database (for SA with T=2, 2.5 and 3 s). Estimated intensity maps are then computed using SA(T=2S) to Modified Mercalli Intensity correlations derived for central Mexico. The maps are made available to the institutions in charge of the disaster prevention systems. In order to analyze the accuracy of the maps, we compare them against observations not considered in the

  19. Modeling of strong ground motion during the 1992 Cairo earthquake in the urban area northern Greater of Cairo, Egypt

    NASA Astrophysics Data System (ADS)

    Omar, Khaled; Attia, Mohsen; Fergany, El Sayed; Hassoup, Awad; Elkhashab, Hussein

    2013-06-01

    The 1992 Cairo earthquake originated from Dahshour seismic zone at an epicentral distance of about 25 km southwest of Cairo. Regardless of its relatively moderate magnitude (Mb = 5.8), it caused extensive property damage besides injuries and loss of lives. The significant damage of this earthquake was probably associated with amplification of seismic waves due to local site effects. Liquefaction was observed at many sites near the epicenter. There are no records of strong ground motion at the damaged area during this earthquake. The main shock was recorded only by the local Kattamya station (KEG) constructed in limestone rock site at about 46-48 km east of Cairo. In the present work, the strong ground motion during 1992 Cairo earthquake was analyzed and the possible causes of damage and structural failure were discussed. The study area is located at the southern part of Cairo city, holding heavy population and many public structures and strategic buildings. The ground motion parameters in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and pseudo-spectral acceleration (PSA) were estimated for each site in the study area and in the KEG site. The site-dependent spectral models together with the stochastic technique were applied for this purpose, using the Fourier amplitude spectrum (FAS) source scaling, attenuation model, and the site amplification functions. The peak ground acceleration of the studied area, comprising 89 sites in northern great of Cairo (Qalyoub city) was calculated. The calculated peak ground acceleration values indicate the sites of high values of peak ground acceleration which are also characterized by high ground motion amplification factors. The ground motion, which is presented in this study, is highly amplified by the soil layer covering the area. Otherwise, the surface layer must be totally removed before construction of the buildings to avoid its large amplification to the ground motion.

  20. "Did you feel it?" Intensity data: A surprisingly good measure of earthquake ground motion

    USGS Publications Warehouse

    Atkinson, G.M.; Wald, D.J.

    2007-01-01

    The U.S. Geological Survey is tapping a vast new source of engineering seismology data through its "Did You Feel It?" (DYFI) program, which collects online citizen responses to earthquakes. To date, more than 750,000 responses have been compiled in the United States alone. The DYFI data make up in quantity what they may lack in scientific quality and offer the potential to resolve longstanding issues in earthquake ground-motion science. Such issues have been difficult to address due to the paucity of instrumental ground-motion data in regions of low seismicity. In particular, DYFI data provide strong evidence that earthquake stress drops, which control the strength of high-frequency ground shaking, are higher in the central and eastern United States (CEUS) than in California. Higher earthquake stress drops, coupled with lower attenuation of shaking with distance, result in stronger overall shaking over a wider area and thus more potential damage for CEUS earthquakes in comparison to those of equal magnitude in California - a fact also definitively captured with these new DYFI data and maps.

  1. Simulations of Ground Motion in Southern California based upon the Spectral-Element Method

    NASA Astrophysics Data System (ADS)

    Tromp, J.; Komatitsch, D.; Liu, Q.

    2003-12-01

    We use the spectral-element method to simulate ground motion generated by recent well-recorded small earthquakes in Southern California. Simulations are performed using a new sedimentary basin model that is constrained by hundreds of petroleum industry well logs and more than twenty thousand kilometers of seismic reflection profiles. The numerical simulations account for 3D variations of seismic wave speeds and density, topography and bathymetry, and attenuation. Simulations for several small recent events demonstrate that the combination of a detailed sedimentary basin model and an accurate numerical technique facilitates the simulation of ground motion at periods of 2 seconds and longer inside the Los Angeles basin and 6 seconds and longer elsewhere. Peak ground displacement, velocity and acceleration maps illustrate that significant amplification occurs in the basin. Centroid-Moment Tensor mechanisms are obtained based upon Pnl and surface waveforms and numerically calculated 3D Frechet derivatives. We use a combination of waveform and waveform-envelope misfit criteria, and facilitate pure double-couple or zero-trace moment-tensor inversions.

  2. Ground Motion Characteristics of the 2011 Virginia and 1988 Quebec M5.8 Earthquakes

    NASA Astrophysics Data System (ADS)

    Assatourians, K.; Atkinson, G. M.

    2011-12-01

    The largest two earthquakes in eastern North America (ENA) in the last 50 years are the 2011 Mineral, Virginia and the 1988 Saguenay, Quebec earthquakes, both of moment magnitude (M) 5.8. Both events were relatively well-recorded at regional distances (especially the Virginia earthquake) but have a disappointing lack of instrumental records at distances within 50 km, confounding interpretation of expected near-source motions for moderate-to-large ENA events. At regional distances (200 to 500 km), over frequencies from 0.5 to 10 Hz, the instrumentally-recorded motions from the Virginia and Quebec earthquakes show similar amplitudes and attenuation trends; in both cases the motions agree reasonably well with the trend lines suggested by recent ground-motion prediction equations (GMPEs) such as those of Atkinson and Boore (2011) and Pezeshk et al. (2011). At distances <200 km, limited recorded data suggest that the Virginia event does not have high-frequency motions (5 to 10 Hz) as strong as those seen in the Saguenay earthquake, while low-frequency motions (0.5 to 1 Hz) appear to be larger for the Virginia event than for Saguenay. We can augment our understanding of the relative differences in ground motions and attenuation using intensity data; intensity data have the advantage of being available at close distances where instrumental records are sparse. Intensities for the Virginia event were approximately 1 unit lower than those for Saguenay at close distances (<40 km), but attenuated more slowly with distance. Attenuation differences might be partly due to the different focal depths of the events (6 km for Virginia, 28 km for Saguenay), which may have resulted in Moho-bounce effects being seen in a different distance range. Both events had a mean radius for intensity 3 of about 600 km. The observed mean intensity of 3 at 600 km is in agreement with the intensity GMPE of Atkinson and Wald (2007); at close distances, the Virginia intensities are lower than predicted

  3. Ground motion following selection of SRS design basis earthquake and associated deterministic approach. Final report: Revision 1

    SciTech Connect

    Not Available

    1991-03-01

    This report summarizes the results of a deterministic assessment of earthquake ground motions at the Savannah River Site (SRS). The purpose of this study is to assist the Environmental Sciences Section of the Savannah River Laboratory in reevaluating the design basis earthquake (DBE) ground motion at SRS during approaches defined in Appendix A to 10 CFR Part 100. This work is in support of the Seismic Engineering Section`s Seismic Qualification Program for reactor restart.

  4. Chapter D. The Loma Prieta, California, Earthquake of October 17, 1989 - Earth Structures and Engineering Characterization of Ground Motion

    USGS Publications Warehouse

    Holzer, Thomas L.

    1998-01-01

    This chapter contains two papers that summarize the performance of engineered earth structures, dams and stabilized excavations in soil, and two papers that characterize for engineering purposes the attenuation of ground motion with distance during the Loma Prieta earthquake. Documenting the field performance of engineered structures and confirming empirically based predictions of ground motion are critical for safe and cost effective seismic design of future structures as well as the retrofitting of existing ones.

  5. Comparison of ground motions from hybrid simulations to nga prediction equations

    USGS Publications Warehouse

    Star, L.M.; Stewart, J.P.; Graves, R.W.

    2011-01-01

    We compare simulated motions for a Mw 7.8 rupture scenario on the San Andreas Fault known as the ShakeOut event, two permutations with different hypocenter locations, and a Mw 7.15 Puente Hills blind thrust scenario, to median and dispersion predictions from empirical NGA ground motion prediction equations. We find the simulated motions attenuate faster with distance than is predicted by the NGA models for periods less than about 5.0 s After removing this distance attenuation bias, the average residuals of the simulated events (i.e., event terms) are generally within the scatter of empirical event terms, although the ShakeOut simulation appears to be a high static stress drop event. The intraevent dispersion in the simulations is lower than NGA values at short periods and abruptly increases at 1.0 s due to different simulation procedures at short and long periods. The simulated motions have a depth-dependent basin response similar to the NGA models, and also show complex effects in which stronger basin response occurs when the fault rupture transmits energy into a basin at low angle, which is not predicted by the NGA models. Rupture directivity effects are found to scale with the isochrone parameter ?? 2011, Earthquake Engineering Research Institute.

  6. Semi-Empirical Characterization of Ground Motions Including Source, Path and Nonlinear Site Effects

    NASA Astrophysics Data System (ADS)

    Seyhan, Emel

    The objective of this thesis is to improve the physical understanding of earthquake ground motion characteristics related to source, path and nonlinear site effects and our ability to model those effects with engineering models. Site database work was performed within the context of the NGA-West 2 project. Starting with the site database from original (2008) NGA project (last edited in 2006), we provided site classifications for 2538 new sites and re-classifications of previous sites. The principal site parameter is the time-averaged shear wave velocity in the upper 30 m (Vs30 ), which is characterized using measurements where available, and proxy-based relationships otherwise. We improved the documentation and consistency of site descriptors used as proxies for the estimation of Vs30, developed evidence-based protocols for Vs30 estimation from available proxies, and augmented estimates of various basin depth parameters. Site factors typically have a small-strain site amplification that captures impedance and resonance effects coupled with nonlinear components. Site factors in current NEHRP Provisions are empirically-derived at relatively small ground motion levels and feature simulation-based nonlinearity. We show that current NEHRP site factors have discrepancies with respect to the site terms in the original NGA GMPEs both in the linear site amplification (especially for Classes B, C, D, and E) and the degree of nonlinearity (Classes C and D). We analyzed the NGA-West 2 dataset and simulation-based models for site amplification to develop a new model. The model has linear and nonlinear additive components. The linear component is fully empirical, being derived from worldwide ground motion data (regional effects were examined but found to not be sufficiently important to be included in the model). The model features linear Vs30-scaling in a log-log sense below a corner velocity (Vc), and no Vs30-scaling for velocities faster than Vc. The nonlinear component is

  7. ARMA models for earthquake ground motions. Seismic safety margins research program

    SciTech Connect

    Chang, M. K.; Kwiatkowski, J. W.; Nau, R. F.; Oliver, R. M.; Pister, K. S.

    1981-02-01

    Four major California earthquake records were analyzed by use of a class of discrete linear time-domain processes commonly referred to as ARMA (Autoregressive/Moving-Average) models. It was possible to analyze these different earthquakes, identify the order of the appropriate ARMA model(s), estimate parameters, and test the residuals generated by these models. It was also possible to show the connections, similarities, and differences between the traditional continuous models (with parameter estimates based on spectral analyses) and the discrete models with parameters estimated by various maximum-likelihood techniques applied to digitized acceleration data in the time domain. The methodology proposed is suitable for simulating earthquake ground motions in the time domain, and appears to be easily adapted to serve as inputs for nonlinear discrete time models of structural motions. 60 references, 19 figures, 9 tables.

  8. Initiation of a Database of CEUS Ground Motions for NGA East

    NASA Astrophysics Data System (ADS)

    Cramer, C. H.

    2007-12-01

    The Nuclear Regulatory Commission has funded the first stage of development of a database of central and eastern US (CEUS) broadband and accelerograph records, along the lines of the existing Next Generation Attenuation (NGA) database for active tectonic areas. This database will form the foundation of an NGA East project for the development of CEUS ground-motion prediction equations that include the effects of soils. This initial effort covers the development of a database design and the beginning of data collection to populate the database. It also includes some processing for important source parameters (Brune corner frequency and stress drop) and site parameters (kappa, Vs30). Besides collecting appropriate earthquake recordings and information, existing information about site conditions at recording sites will also be gathered, including geology and geotechnical information. The long-range goal of the database development is to complete the database and make it available in 2010. The database design is centered on CEUS ground motion information needs but is built on the Pacific Earthquake Engineering Research Center's (PEER) NGA experience. Documentation from the PEER NGA website was reviewed and relevant fields incorporated into the CEUS database design. CEUS database tables include ones for earthquake, station, component, record, and references. As was done for NGA, a CEUS ground- motion flat file of key information will be extracted from the CEUS database for use in attenuation relation development. A short report on the CEUS database and several initial design-definition files are available at https://umdrive.memphis.edu:443/xythoswfs/webui/_xy-7843974_docstore1. Comments and suggestions on the database design can be sent to the author. More details will be presented in a poster at the meeting.

  9. Weather-related Ground Motions Recorded by Taiwan Broadband Seismic Network Stations

    NASA Astrophysics Data System (ADS)

    Yang, C. F.; Chi, W. C.

    2014-12-01

    Broadband seismometers record ground motions, which can be induced by weather-related processes. Analyzing such signals might help to better understand those natural processes. Previously, abnormal seismic signals have been detected during rainfall and snowmelt events. The amplitudes of those seismic signals correlated with the variations of the discharge in a nearby river and scientists have proposed that such signals were generated by bed load transport. Here, we used the continuous seismic data from the Broadband Array in Taiwan for Seismology (BATS) to analyze the weather-related ground motions during rainfall events. The sampling rate for seismic data is 100 samples per second. We compared the seismic data with the precipitation data from the rain gauge stations in Taiwan in three select rainfall periods, Typhoon Kalmaegi in 2008, Typhoon Morakot in 2009 and the East Asian rainy season in 2012. During raining, the Power Spectral Density (PSD) of high frequency (> 1 Hz) seismic noises is apparently high, and the amplitude of the seismic noise also correlates with the local precipitation, especially at the stations in the drainage basins, and the PSD decreased gradually after peaks of precipitation. At some seismic stations, we observed vertical ground motions at several bands of frequencies: 0-1 Hz, 1-5 Hz, and 5-45 Hz. However, on horizontal components we found the 5-45 Hz energy splits into two bands: 5-25 Hz and 30-45 Hz. For stations near the ridge tops or on the coastal plain, the 30-45 Hz band energy is weaker or missing. Preliminary results show that the amplitudes of the seismic waves correlate with the stream flow discharge. Next, we plan to study the sources of the different bands of energy to examine if we can monitor and quantify natural processes, like precipitation and river discharge, using seismic signals.

  10. On the coherence of ground motion in the San Fernando valley

    USGS Publications Warehouse

    Hough, S.E.; Field, E.H.

    1996-01-01

    We present an analysis of the coherence of seismic ground motion recorded on alluvial sediments in the San Fernando Valley, California. Using aftershocks of the 17 January 1994 Mw6.7 earthquake recorded at a quasi-dense array of portable stations, we analyze the coherence of three well-recorded magnitude 3.7 to 4.0 events over the frequency range 0.5 to 15 Hz and a distance range of 0.5 to 5.3 km. All stations are located at sites with broadly similar near-site geology, characterized by medium to fine-grain Quaternary alluvial sediments. On average, relatively high values of coherence are observed for distances up to 3 to 4 km and frequencies up to 2 to 3 Hz; coherence drops sharply at frequencies near and above 3 Hz. Although average coherence functions are described reasonably well by a log-linear relationship with frequency, the curves at all distances exhibit a flattening at low frequencies that is not consistent with previous observations of coherence at hardrock sites. The distance decay of coherence is also markedly less strong, with high coherence values observed over station separations corresponding to multiple wavelengths. This may reflect fundamental differences in shallow-wave propagation in the two environments, with high-frequency scattering relatively more dominant in regions of hard-rock near-surface geology. Within a sedimentary basin or valley, the site response itself generally reflects a resonance phenomenon that may tend to give rise to more uniform ground motions. However, previous studies have demonstrated the existence of pathological focusing and amplification effects within complex sedimentary basin environments such as the greater Los Angeles region; our results undoubtedly do not quantify the full range of ground-motion variability at all sites, but rather represent the level of that variability that can be expected, and quantified, for typical source/receiver paths.

  11. A summary of ground motion effects at SLAC (Stanford Linear Accelerator Center) resulting from the Oct 17th 1989 earthquake

    SciTech Connect

    Ruland, R.E.

    1990-08-01

    Ground motions resulting from the October 17th 1989 (Loma Prieta) earthquake are described and can be correlated with some geologic features of the SLAC site. Recent deformations of the linac are also related to slow motions observed over the past 20 years. Measured characteristics of the earthquake are listed. Some effects on machine components and detectors are noted. 18 refs., 16 figs.

  12. Modelling Strong Ground Motions for Subduction Events in the Wellington Region, New Zealand

    NASA Astrophysics Data System (ADS)

    Francois-Holden, C.; Zhao, J.

    2010-12-01

    This work is a part of the “It’s Our Fault” programme, whose goal is to make Wellington, New Zealand, a more resilient city regarding earthquake hazards. We are working on defining ground motions from large plate boundary earthquakes at specified locations in the Wellington region in terms of response spectra and acceleration time histories. These motions will provide input for risk modelling for a potential major earthquake additional to those associated with the active faults of the region. Broadband waveforms are modelled applying the hybrid technique combining deterministic and stochastic approaches. We follow the proposed recipe by Irikura et al. (2004) to predict strong ground motions. We validated Irikura’s code and recipe using the strong motion dataset from the 2003 Mw 7.2 Fiordland earthquake, with both empirical and stochastic Green’s functions. The method was satisfactorily tested using an intraslab rupture and a record from a nearby aftershock as the empirical Green’s function (EGF). Although the event generated many aftershocks, it was difficult to find small events with 2 orders of magnitude smaller than the mainshock, recorded at a well distributed set of stations, with a rupture mechanism close enough to the mainshock. The alternative to using EGF is the stochastic Green’s functions (SGF) approach. We chose the Motazedian and Atkinson (2005) method for its assumption of a finite fault source model (instead of a point source). This assumption is closer to reality for Green’s functions in our case study where events have magnitudes greater than 5, and distances less than 200 km. We are now applying this method to a source scenario representing a locked interface underneath Wellington. A range of rupture scenarios will be modelled with varying hypocentre location, asperity locations, and overall rupture area. Finally, recent advances in detailed modelling of the Wellington basin geology will allow us to include site effects in our

  13. On low-frequency errors of uniformly modulated filtered white-noise models for ground motions

    USGS Publications Warehouse

    Safak, Erdal; Boore, David M.

    1988-01-01

    Low-frequency errors of a commonly used non-stationary stochastic model (uniformly modulated filtered white-noise model) for earthquake ground motions are investigated. It is shown both analytically and by numerical simulation that uniformly modulated filter white-noise-type models systematically overestimate the spectral response for periods longer than the effective duration of the earthquake, because of the built-in low-frequency errors in the model. The errors, which are significant for low-magnitude short-duration earthquakes, can be eliminated by using the filtered shot-noise-type models (i. e. white noise, modulated by the envelope first, and then filtered).

  14. Seismology and Earthquake Ground Motions of the August 24, 2014 M6 South Napa Earthquake

    NASA Astrophysics Data System (ADS)

    Kishida, T.; Wang, S.; Mazzoni, S.; Markam, C.; Lu, Y.; Bozorgnia, Y.; Mahin, S.; Bray, J.; Panagiotou, M.; Stewart, J. P.; Darragh, R. B.; Abrahamson, N. A.; Hollenback, J. C.; Gutierrez, C.; Chiou, B.; Muin, S.; Dreger, D. S.

    2014-12-01

    The M6.0 South Napa earthquake produced strong ground motions in the northern San Francisco Bay area. A total of 214 three-component uncorrected digital accelerograms were downloaded from the CESMD website and processed following the PEER standard procedure (Ancheta et al. 2014). Intense ground motions were recorded in the heavily damaged area of Napa with peak acceleration greater than 0.3 g. Pulse-like waveforms were observed in several of the velocity time series at the near-fault stations. Near-fault velocity time series were rotated into fault normal and fault parallel directions and then characterized as pulse-like or non pulse-like according to previous studies by Hayden et al. (2014), Shahi (2013), and Lu and Panagiotou (2014). The near-fault velocity time series at five stations contained pulses with periods within the expected range of 0.7 s to 2.0 s for soil sites (Bray et al. 2009). However, they also contained longer period pulses than the expected range. High-frequency spikes were recorded at Carquinez Bridge Geotechnical Array #1 (CBGA1) of approximately 1.0 g on the NS component. These spikes were in the S-wave portion and were consistently observed in the downhole arrays and several other sites along the same azimuth from the source. The spikes increase in amplitude both from the Hwy 37/Napa River East Geotechnical Array to CBGA1 and from a depth below 100 m to the surface. This suggests that the spikes could be a result of path effects and site amplification through the surficial soft soil deposits. However, these observations do not exclude the possibility of soil-structure interaction effects on the measured recordings. The 5% damped pseudo-spectral accelerations (PSA) from the recorded ground motions compared well to those estimated from the recent NGA-West2 GMPEs. The exceptions are that PSA is under predicted from 1 to 3 seconds at several near fault records due to the velocity pulses and for short periods at Carquinez Bridge where the large

  15. Hydrostatic Level Sensors as High Precision Ground Motion Instrumentation for Tevatron and Other Energy Frontier Accelerators

    SciTech Connect

    Volk, James; Hansen, Sten; Johnson, Todd; Jostlein, Hans; Kiper, Terry; Shiltsev, Vladimir; Chupyra, Andrei; Kondaurov, Mikhail; Medvedko, Anatoly; Parkhomchuk, Vasily; Singatulin, Shavkat

    2012-01-01

    Particle accelerators require very tight tolerances on the alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the Hydrostatic Level Sensors (HLS) for very low frequency measurements used in a variety of facilities at Fermilab. We present design features of the sensors, outline their technical parameters, describe their test and calibration procedures, discuss different regimes of operation and give few illustrative examples of the experimental data. Detail experimental results of the ground motion measurements with these detectors will be presented in subsequent papers.

  16. Effect of NGA West-2 Predictive Ground Motion Equations on Loss

    NASA Astrophysics Data System (ADS)

    Jemberie, A. L.

    2014-12-01

    Individual Predictive Ground Motion Equations (PGMEs) of the NGA West-2 project have been analyzed for possible differences in loss for certain locations in California. Differences between the individual hazard curves are pronounced in the loss results. The differences are more than a factor of 2 for longer return periods between the Gross losses from the individual PGMEs. Similar differences are also found between the Average Annual Losses from the individual PGMEs. This indicates the difficulty in choosing any one of the PGMEs except using the weighted average of them. Comparisons between losses from the 2008 and 2014 models are also reported.

  17. Stress Drop and Its Relationship to Radiated Energy, Ground Motion and Uncertainty

    NASA Astrophysics Data System (ADS)

    Baltay, A.

    2014-12-01

    Despite the seemingly diverse circumstances under which crustal earthquakes occur, scale-invariant stress drop and apparent stress, the ratio of radiated seismic energy to moment, is observed. The magnitude-independence of these parameters is central to our understanding of both earthquake physics and strong ground motion genesis. Estimates of stress drop and radiated energy, however, display large amounts of scatter potentially masking any secondary trends in the data. We investigate sources of this uncertainty within the framework of constant stress drop and apparent stress. We first re-visit estimates of energy and stress drop from a variety of earthquake observations and methods, for events ranging from magnitude ~2 to ~9. Using an empirical Green's function (eGf) deconvolution method, which removes the path and site effects, radiated energy and Brune stress drop are estimated for both regional events in the western US and Eastern Honshu, Japan from the HiNet network, as well as teleseismically recorded global great earthquakes [Baltay et al., 2010, 2011, 2014]. In addition to eGf methods, ground-motion based metrics for stress drop are considered, using both KikNet data from Japan [Baltay et al., 2013] and the NGA-West2 data, a very well curated ground-motion database. Both the eGf-based stress drop estimates and those from the NGA-West2 database show a marked decrease in scatter, allowing us to identify deterministic secondary trends in stress drop. We find both an increasing stress drop with depth, as well as a larger stress drop of about 30% on average for mainshock events as compared to on-fault aftershocks. While both of these effects are already included in some ground-motion prediction equations (GMPE), many previous seismological studies have been unable to conclusively uncover these trends because of their considerable scatter. Elucidating these effects in the context of reduced and quantified epistemic uncertainty can help both seismologists and

  18. Earthquake Strong Ground Motion Scenario at the 2008 Olympic Games Sites, Beijing, China

    NASA Astrophysics Data System (ADS)

    Liu, L.; Rohrbach, E. A.; Chen, Q.; Chen, Y.

    2006-12-01

    Historic earthquake record indicates mediate to strong earthquakes have been frequently hit greater Beijing metropolitan area where is going to host the 2008 summer Olympic Games. For the readiness preparation of emergency response to the earthquake shaking for a mega event in a mega city like Beijing in summer 2008, this paper tries to construct the strong ground motion scenario at a number of gymnasium sites for the 2008 Olympic Games. During the last 500 years (the Ming and Qing Dynasties) in which the historic earthquake record are thorough and complete, there are at least 12 earthquake events with the maximum intensity of VI or greater occurred within 100 km radius centered at the Tiananmen Square, the center of Beijing City. Numerical simulation of the seismic wave propagation and surface strong ground motion is carried out by the pseudospectral time domain methods with viscoelastic material properties. To improve the modeling efficiency and accuracy, a multi-scale approach is adapted: the seismic wave propagation originated from an earthquake rupture source is first simulated by a model with larger physical domain with coarser grids. Then the wavefield at a given plane is taken as the source input for the small-scale, fine grid model for the strong ground motion study at the sites. The earthquake source rupture scenario is based on two particular historic earthquake events: One is the Great 1679 Sanhe-Pinggu Earthquake (M~8, Maximum Intensity XI at the epicenter and Intensity VIII in city center)) whose epicenter is about 60 km ENE of the city center. The other one is the 1730 Haidian Earthquake (M~6, Maximum Intensity IX at the epicenter and Intensity VIII in city center) with the epicentral distance less than 20 km away from the city center in the NW Haidian District. The exist of the thick Tertiary-Quaternary sediments (maximum thickness ~ 2 km) in Beijing area plays a critical role on estimating the surface ground motion at the Olympic Games sites, which

  19. Deaggregation of Probabilistic Ground Motions in the Central and Eastern United States

    USGS Publications Warehouse

    Harmsen, S.; Perkins, D.; Frankel, A.

    1999-01-01

    Probabilistic seismic hazard analysis (PSHA) is a technique for estimating the annual rate of exceedance of a specified ground motion at a site due to known and suspected earthquake sources. The relative contributions of the various sources to the total seismic hazard are determined as a function of their occurrence rates and their ground-motion potential. The separation of the exceedance contributions into bins whose base dimensions are magnitude and distance is called deaggregation. We have deaggregated the hazard analyses for the new USGS national probabilistic ground-motion hazard maps (Frankel et al., 1996). For points on a 0.2?? grid in the central and eastern United States (CEUS), we show color maps of the geographical variation of mean and modal magnitudes (M??, M??) and distances (D??, D??) for ground motions having a 2% chance of exceedance in 50 years. These maps are displayed for peak horizontal acceleration and for spectral response accelerations of 0.2, 0.3, and 1.0 sec. We tabulate M??, D??, M??, and D?? for 49 CEUS cities for 0.2- and 1.0-sec response. Thus, these maps and tables are PSHA-derived estimates of the potential earthquakes that dominate seismic hazard at short and intermediate periods in the CEUS. The contribution to hazard of the New Madrid and Charleston sources dominates over much of the CEUS; for 0.2-sec response, over 40% of the area; for 1.0-sec response, over 80% of the area. For 0.2-sec response, D?? ranges from 20 to 200 km, for 1.0 sec, 30 to 600 km. For sites influenced by New Madrid or Charleston, D is less than the distance to these sources, and M?? is less than the characteristic magnitude of these sources, because averaging takes into account the effect of smaller magnitude and closer sources. On the other hand, D?? is directly the distance to New Madrid or Charleston and M?? for 0.2- and 1.0-sec response corresponds to the dominating source over much of the CEUS. For some cities in the North Atlantic states, short

  20. Identifying the Unique Ground Motion Signatures of Supershear Earthquakes: Theory and Experiments

    NASA Astrophysics Data System (ADS)

    Mello, Michael

    The near-field ground motion signatures associated with sub-Rayleigh and supershear ruptures are investigated using the laboratory earthquake experiment originally developed by Rosakis and co-workers (Xia et al., 2004, 2005; Lu et al., 2007; Rosakis et al., 2007). Heterodyne laser interferometers enable continuous, high-bandwidth measurements of fault-normal (FN), fault-parallel (FP), and vertical (V) particle velocity ``ground motion" records at discrete locations on the surface of a Homalite-100 test specimen as a sub-Rayleigh or a supershear rupture sweeps along the frictional fault. Photoelastic interference fringes, acquired using high-speed digital photography, provide a synchronized, spatially resolved, whole field view of the advancing rupture tip and surrounding maximum shear stress field. The first phase of experimental investigations examine and verify the ground motion signatures of supershear ruptures. Experimental results demonstrate that a shear Mach front produced by a stable supershear rupture is characterized by a dominant FP velocity component. The situation is shown to reverse in the sub-Rayleigh rupture speed regime whereby the FN particle velocity component dominates the ground motion record. Additional distinguishing particle velocity signatures, consistent with theoretical and numerical predictions, and repeatedly observed in experimental records are, (1) a pronounced peak in the FP velocity record induced by the leading dilatational field, which sweeps the measurement station in advance of the shear Mach front, and (2) a pronounced velocity swing in the FN record associated with the arrival of a trailing Rayleigh sub-Rayleigh (secondary) rupture, which follows the arrival of the shear Mach front. Analysis of the particle velocity records also confirms 2D steady-state theoretical predictions pertaining to the separation, attenuation, and radiation partitioning of the shear and dilatational portions of the rupture velocity field components

  1. Seismic hazard assessment for Myanmar: Earthquake model database, ground-motion scenarios, and probabilistic assessments

    NASA Astrophysics Data System (ADS)

    Chan, C. H.; Wang, Y.; Thant, M.; Maung Maung, P.; Sieh, K.

    2015-12-01

    We have constructed an earthquake and fault database, conducted a series of ground-shaking scenarios, and proposed seismic hazard maps for all of Myanmar and hazard curves for selected cities. Our earthquake database integrates the ISC, ISC-GEM and global ANSS Comprehensive Catalogues, and includes harmonized magnitude scales without duplicate events. Our active fault database includes active fault data from previous studies. Using the parameters from these updated databases (i.e., the Gutenberg-Richter relationship, slip rate, maximum magnitude and the elapse time of last events), we have determined the earthquake recurrence models of seismogenic sources. To evaluate the ground shaking behaviours in different tectonic regimes, we conducted a series of tests by matching the modelled ground motions to the felt intensities of earthquakes. Through the case of the 1975 Bagan earthquake, we determined that Atkinson and Moore's (2003) scenario using the ground motion prediction equations (GMPEs) fits the behaviours of the subduction events best. Also, the 2011 Tarlay and 2012 Thabeikkyin events suggested the GMPEs of Akkar and Cagnan (2010) fit crustal earthquakes best. We thus incorporated the best-fitting GMPEs and site conditions based on Vs30 (the average shear-velocity down to 30 m depth) from analysis of topographic slope and microtremor array measurements to assess seismic hazard. The hazard is highest in regions close to the Sagaing Fault and along the Western Coast of Myanmar as seismic sources there have earthquakes occur at short intervals and/or last events occurred a long time ago. The hazard curves for the cities of Bago, Mandalay, Sagaing, Taungoo and Yangon show higher hazards for sites close to an active fault or with a low Vs30, e.g., the downtown of Sagaing and Shwemawdaw Pagoda in Bago.

  2. Ground motion prediction and earthquake scenarios in the volcanic region of Mt. Etna (Southern Italy

    NASA Astrophysics Data System (ADS)

    Langer, Horst; Tusa, Giuseppina; Luciano, Scarfi; Azzaro, Raffaela

    2013-04-01

    One of the principal issues in the assessment of seismic hazard is the prediction of relevant ground motion parameters, e. g., peak ground acceleration, radiated seismic energy, response spectra, at some distance from the source. Here we first present ground motion prediction equations (GMPE) for horizontal components for the area of Mt. Etna and adjacent zones. Our analysis is based on 4878 three component seismograms related to 129 seismic events with local magnitudes ranging from 3.0 to 4.8, hypocentral distances up to 200 km, and focal depth shallower than 30 km. Accounting for the specific seismotectonic and geological conditions of the considered area we have divided our data set into three sub-groups: (i) Shallow Mt. Etna Events (SEE), i.e., typically volcano-tectonic events in the area of Mt. Etna having a focal depth less than 5 km; (ii) Deep Mt. Etna Events (DEE), i.e., events in the volcanic region, but with a depth greater than 5 km; (iii) Extra Mt. Etna Events (EEE), i.e., purely tectonic events falling outside the area of Mt. Etna. The predicted PGAs for the SEE are lower than those predicted for the DEE and the EEE, reflecting their lower high-frequency energy content. We explain this observation as due to the lower stress drops. The attenuation relationships are compared to the ones most commonly used, such as by Sabetta and Pugliese (1987)for Italy, or Ambraseys et al. (1996) for Europe. Whereas our GMPEs are based on small earthquakes, the magnitudes covered by the two above mentioned attenuation relationships regard moderate to large magnitudes (up to 6.8 and 7.9, respectively). We show that the extrapolation of our GMPEs to magnitues beyond the range covered by the data is misleading; at the same time also the afore mentioned relationships fail to predict ground motion parameters for our data set. Despite of these discrepancies, we can exploit our data for setting up scenarios for strong earthquakes for which no instrumental recordings are

  3. Wind-Tunnel Investigation of the Horizontal Motion of a Wing Near the Ground

    NASA Technical Reports Server (NTRS)

    Serebrisky, Y. M.; Biachuev, S. A.

    1946-01-01

    By the method of images the horizontal steady motion of a wing at small heights above the ground was investigated in the wind tunnel, A rectangular wing with Clark Y-H profile was tested with and without flaps. The distance from the trailing edge of the wing to the ground was varied within the limits 0.75 less than or = s/c less than or = 0.25. Measurements were made of the lift, the drag, the pitching moment, and the pressure distribution at one section. For a wing without flaps and one with flaps a considereble decrease in the lift force and a,drop in the drag was obtained at angles of attack below stalling. The flow separation near the ground occurs at smaller angles of attack than is the case for a great height above the ground. At horizontal steady flight for practical values of the height above the ground the maximum lift coefficient for the wing without flaps changes little, but markedly decreases for the wing with flaps. Analysis of these phenomena involves the investigation of the pressure distribution. The pressure distribution curves showed that the changes occurring near the ground are not equivalent to a change in the angle of attack. At the lower surface of the section a very strong increase in the pressures is observed. The pressure changes on the upper surface at angles of attack below stalling are insignificant and lead mainly to an increase in the unfavorable pressure gradient, resulting in the earlier occurrence of separation. For a wing with flaps at large angles of attack for distances from the trailing edge of the flap to the ground less than 0.5 chord, the flow between the wing end the ground is retarded so greatly that the pressure coefficient at the lower surface of the section is very near its limiting value (P = 1), and any further possibility of increase in the pressure is very small. In the application an approximate computation procedure is given of the change of certain aerodynamic characteristics for horizontal steady flight near the

  4. Summary of ground motion prediction results for Nevada Test Site underground nuclear explosions related to the Yucca Mountain project

    SciTech Connect

    Walck, M.C.

    1996-10-01

    This report summarizes available data on ground motions from underground nuclear explosions recorded on and near the Nevada Test Site, with emphasis on the ground motions recorded at stations on Yucca Mountain, the site of a potential high-level radioactive waste repository. Sandia National Laboratories, through the Weapons Test Seismic Investigations project, collected and analyzed ground motion data from NTS explosions over a 14-year period, from 1977 through 1990. By combining these data with available data from earlier, larger explosions, prediction equations for several ground motion parameters have been developed for the Test Site area for underground nuclear explosion sources. Also presented are available analyses of the relationship between surface and downhole motions and spectra and relevant crustal velocity structure information for Yucca Mountain derived from the explosion data. The data and associated analyses demonstrate that ground motions at Yucca Mountain from nuclear tests have been at levels lower than would be expected from moderate to large earthquakes in the region; thus nuclear explosions, while located relatively close, would not control seismic design criteria for the potential repository.

  5. Application of universal kriging for estimation of earthquake ground motion: Statistical significance of results

    SciTech Connect

    Carr, J.R.; Roberts, K.P.

    1989-02-01

    Universal kriging is compared with ordinary kriging for estimation of earthquake ground motion. Ordinary kriging is based on a stationary random function model; universal kriging is based on a nonstationary random function model representing first-order drift. Accuracy of universal kriging is compared with that for ordinary kriging; cross-validation is used as the basis for comparison. Hypothesis testing on these results shows that accuracy obtained using universal kriging is not significantly different from accuracy obtained using ordinary kriging. Test based on normal distribution assumptions are applied to errors measured in the cross-validation procedure; t and F tests reveal no evidence to suggest universal and ordinary kriging are different for estimation of earthquake ground motion. Nonparametric hypothesis tests applied to these errors and jackknife statistics yield the same conclusion: universal and ordinary kriging are not significantly different for this application as determined by a cross-validation procedure. These results are based on application to four independent data sets (four different seismic events).

  6. Evaluation of ground motion scaling methods for analysis of structural systems

    USGS Publications Warehouse

    O'Donnell, A. P.; Beltsar, O.A.; Kurama, Y.C.; Kalkan, E.; Taflanidis, A.A.

    2011-01-01

    Ground motion selection and scaling comprises undoubtedly the most important component of any seismic risk assessment study that involves time-history analysis. Ironically, this is also the single parameter with the least guidance provided in current building codes, resulting in the use of mostly subjective choices in design. The relevant research to date has been primarily on single-degree-of-freedom systems, with only a few studies using multi-degree-of-freedom systems. Furthermore, the previous research is based solely on numerical simulations with no experimental data available for the validation of the results. By contrast, the research effort described in this paper focuses on an experimental evaluation of selected ground motion scaling methods based on small-scale shake-table experiments of re-configurable linearelastic and nonlinear multi-story building frame structure models. Ultimately, the experimental results will lead to the development of guidelines and procedures to achieve reliable demand estimates from nonlinear response history analysis in seismic design. In this paper, an overview of this research effort is discussed and preliminary results based on linear-elastic dynamic response are presented. ?? ASCE 2011.

  7. Ground motion in the presence of complex topography: Earthquake and ambient noise sources

    USGS Publications Warehouse

    Hartzell, Stephen; Meremonte, Mark; Ramírez-Guzmán, Leonardo; McNamara, Daniel

    2014-01-01

    To study the influence of topography on ground motion, eight seismic recorders were deployed for a period of one year over Poverty Ridge on the east side of the San Francisco Bay Area, California. This location is desirable because of its proximity to local earthquake sources and the significant topographic relief of the array (439 m). Topographic amplification is evaluated as a function of frequency using a variety of methods, including reference‐site‐based spectral ratios and single‐station horizontal‐to‐vertical spectral ratios using both shear waves from earthquakes and ambient noise. Field observations are compared with the predicted ground motion from an accurate digital model of the topography and a 3D local velocity model. Amplification factors from the theoretical calculations are consistent with observations. The fundamental resonance of the ridge is prominently observed in the spectra of data and synthetics; however, higher‐frequency peaks are also seen primarily for sources in line with the major axis of the ridge, perhaps indicating higher resonant modes. Excitations of lateral ribs off of the main ridge are also seen at frequencies consistent with their dimensions. The favored directions of resonance are shown to be transverse to the major axes of the topographic features.

  8. UC Berkeley Seismic Guidelines, Appendix II: Ground Motion Time Histories for the UC Berkeley Campus

    SciTech Connect

    Authors, Various

    2003-06-03

    Three sets of ten time histories each were developed to represent the ground motions for each of the three return periods. All of the time histories are provided as pairs of fault-normal and fault-parallel components. The ground motion time histories are provided in two forms: unmodified, and spectrally modified to match the probabilistic response spectra. The unmodified time histories can be scaled to match the probabilistic response spectra at a specified period, such as the first mode period of the structure being analyzed, while leaving the shape of the response spectrum unmodified. This approach preserves the particular characteristics of the individual time history, together with the peaks and troughs of its response spectrum. These individual characteristics are modified in the spectrally matched time histories, resulting in a suite of ten time histories (for a given return period) that all have the same response spectrum for a given component (fault normal or fault parallel) that follows the smooth shape of the probabilistic response spectrum.

  9. UC Berkeley Seismic Guidelines, Appendix II: Ground Motion TimeHistories for the UC Berkeley Campus

    SciTech Connect

    Various

    2003-06-03

    Three sets of ten time histories each were developed to represent the ground motions for each of the three return periods. All of the time histories are provided as pairs of fault-normal and fault-parallel components. The ground motion time histories are provided in two forms: unmodified, and spectrally modified to match the probabilistic response spectra. The unmodified time histories can be scaled to match the probabilistic response spectra at a specified period, such as the first mode period of the structure being analyzed, while leaving the shape of the response spectrum unmodified. This approach preserves the particular characteristics of the individual time history, together with the peaks and troughs of its response spectrum. These individual characteristics are modified in the spectrally matched time histories, resulting in a suite of ten time histories (for a given return period) that all have the same response spectrum for a given component (fault normal or fault parallel) that follows the smooth shape of the probabilistic response spectrum.

  10. Ground motions around a semicircular canyon with a dipping edge under SH plane wave incidence

    NASA Astrophysics Data System (ADS)

    Chang, Kao-Hao; Tsaur, Deng-How; Wang, Jeen-Hwa

    2016-01-01

    In order to explore the spatial distribution and temporal variation of ground motions near a semicircular canyon with a dipping edge, a simplified mathematical model is constructed. Based on the region-matching technique, a Fourier-Bessel series solution for the plane SH-wave excitation is derived and then applied to theoretically simulate the seismic response of the canyon. The use of the adequate wavefunctions and a newly derived Graf's addition formula can solve the unknown expansion coefficients. Parametric analyses with respect to the frequency of input motion, angle of incidence, and canyon geometry are illustrated. Both frequency- and time-domain computations are presented. The canonical case, a completed semicircular canyon, which has the exact analytical solution, and the horizontally truncated case analyzed in previous works are considered as particular cases of the proposed general model. Comparisons with boundary-element solutions show good agreement. Steady-state results show that the phenomenon of wave focusing tends to be significant when the incident angle bends toward the horizontal ground surface. Propagation and attenuation of scattered waves that originated from the surficial anomaly are exhibited in transient-state simulations.

  11. Reno Area Basin Seismic Response: Ground Motion Simulation in Reno, Nevada

    NASA Astrophysics Data System (ADS)

    Pancha, A.; Louie, J.; Anderson, J. G.

    2002-12-01

    A three-dimensional seismic velocity model is being constructed for the Reno Basin and surrounding region for the purpose of modeling basin effects on the ground motion from potential earthquakes. The model specifies seismic velocities, density, and attenuation on a three dimensional grid (120 km x133 km), down to a depth of 40 km. The background model is based on Western Great Basin geology. Published velocity models and new geophysical data are incorporated to constrain the model. Ground motions from recent earthquakes (Mw4.4 12/02/2000 Truckee event; Mw5.2 08/10/2001 Mohawk Valley) are simulated by a fourth order, 3D staggered grid elastic finite difference code (e3d; Larsen, Schultz, and Grieger), and compared with data recorded by local network and nearby broadband IRIS instruments. These e3d synthetics have an upper frequency limit of 0.3 to 0.6 Hz. 1D synthetic Green's functions, computed in a layered elastic solid using the generalized reflection and transmission coefficients, are also compared to both the real seismogram data and the e3d synthetics. Depending on the station, data are above the noise level at frequencies as low as 0.2 Hz, giving a lower frequency limit for comparison. Success is achieved in matching arrival times. Current work focuses on validating and improving the velocity model.

  12. Evaluation of modal pushover-based scaling of one component of ground motion: Tall buildings

    USGS Publications Warehouse

    Kalkan, Erol; Chopra, Anil K.

    2012-01-01

    Nonlinear response history analysis (RHA) is now increasingly used for performance-based seismic design of tall buildings. Required for nonlinear RHAs is a set of ground motions selected and scaled appropriately so that analysis results would be accurate (unbiased) and efficient (having relatively small dispersion). This paper evaluates accuracy and efficiency of recently developed modal pushover–based scaling (MPS) method to scale ground motions for tall buildings. The procedure presented explicitly considers structural strength and is based on the standard intensity measure (IM) of spectral acceleration in a form convenient for evaluating existing structures or proposed designs for new structures. Based on results presented for two actual buildings (19 and 52 stories, respectively), it is demonstrated that the MPS procedure provided a highly accurate estimate of the engineering demand parameters (EDPs), accompanied by significantly reduced record-to-record variability of the responses. In addition, the MPS procedure is shown to be superior to the scaling procedure specified in the ASCE/SEI 7-05 document.

  13. Review of seismicity and ground motion studies related to development of seismic design at SRS

    SciTech Connect

    Stephenson, D.E.; Acree, J.R.

    1992-08-01

    The NRC response spectra developed in Reg. Guide 1.60 is being used in the studies related to restarting of the existing Savannah River Site (SRS) reactors. Because it envelopes all the other site specific spectra which have been developed for SRS, it provides significant conservatism in the design and analysis of the reactor systems for ground motions of this value or with these probability levels. This spectral shape is also the shape used for the design of the recently licensed Vogtle Nuclear Station, located south of the Savannah River from the SRS. This report provides a summary of the data base used to develop the design basis earthquake. This includes the seismicity, rates of occurrence, magnitudes, and attenuation relationships. A summary is provided for the studies performed and methodologies used to establish the design basis earthquake for SRS. The ground motion response spectra developed from the various studies are also summarized. The seismic hazard and PGA`s developed for other critical facilities in the region are discussed, and the SRS seismic instrumentation is presented. The programs for resolving outstanding issues are discussed and conclusions are presented.

  14. Adaptation of the S-5-S pendulum seismometer for measurement of rotational ground motion

    NASA Astrophysics Data System (ADS)

    Knejzlík, Jaromír; Kaláb, Zdeněk; Rambouský, Zdeněk

    2012-10-01

    The Russian electrodynamic seismometer model S-5-S has been adapted for the measurement of rotational ground motion. The mechanical system of the original S-5-S seismometer consists of electrodynamic sensing and damping transducer coils mounted on an asymmetrical double-arm pendulum. This pendulum is suspended on a footing using two pairs of crossed flat springs, which operate as the axis of rotation. The pendulum is stabilised by an additional spring. The S-5-S can be used either as a vertical or as a horizontal sensor. The adaptation of the S-5-S seismometer described below involves removal of the additional spring and installation of an additional mass on the damping arm. Strain gauge angle sensors are installed on one pair of the crossed flat springs. The main dynamic parameters of the rotational seismometer created in this way, i.e. the natural period and damping, are controlled electronically by feedback currents proportional to the angular displacement and angular velocity, both fed to the damping transducer coil. This new seismometer, named the S-5-SR, enables measurement of the rotational component of ground motion around the horizontal or the vertical axes. The output signal from this S-5-SR seismometer can be proportional either to rotational displacement or rotational velocity.

  15. Ground Motion Zoning of Santiago de Cuba: An Approach by SH Waves Modelling

    NASA Astrophysics Data System (ADS)

    Alvarez, Leonardo; García, Julio; Vaccari, Franco; Panza, Giuliano F.; González, Bertha; Reyes, Carmen; Fernández, Bárbara; Pico, Ramón; Zapata, José A.; Arango, Enrique

    The expected ground motion in Santiago de Cuba basin from earthquakes which occurred in the Oriente fault zone is studied. Synthetic SH-waves seismograms have been calculated along four profiles in the basin by the hybrid approach (modal summation for the path source-profile and finite differences for the profile) for a maximum frequency of 1 Hz. The response spectra ratio (RSR) has been determined in 49 sites, distributed along all considered profiles with a spacing of 900 m. The corresponding RSR versus frequency curves have been classified using a logical-combinatorial algorithm. The results of the classification, in combination with the uppermost geological setting (geotechnical information and geological geometry of the subsoil) are used for the seismic zoning of the city. Three different main zones are identified, and a small sector characterized by major resonance effects, due to the particular structural conditions. Each zone is characterized in terms of its expected ground motion parameters for the most probable strong earthquake (MS=7), and for the maximum possible (MS=8).

  16. 6.9 Sikkim Earthquake and Modeling of Ground Motions to Determine Causative Fault

    NASA Astrophysics Data System (ADS)

    Chopra, Sumer; Sharma, Jyoti; Sutar, Anup; Bansal, B. K.

    2014-07-01

    In this study, source parameters of the September 18, 2011 M w 6.9, Sikkim earthquake were determined using acceleration records. These parameters were then used to generate strong motion at a number of sites using the stochastic finite fault modeling technique to constrain the causative fault plane for this earthquake. The average values of corner frequency, seismic moment, stress drop and source radius were 0.12 Hz, 3.07 × 1026 dyne-cm, 115 bars and 9.68 km, respectively. The fault plane solution showed strike-slip movement with two nodal planes oriented along two prominent lineaments in the region, the NE-oriented Kanchendzonga and NW-oriented Tista lineaments. The ground motions were estimated considering both the nodal planes as causative faults and the results in terms of the peak ground accelerations (PGA) and Fourier spectra were then compared with the actual recordings. We found that the NW-SE striking nodal plane along the Tista lineament may have been the causative fault for the Sikkim earthquake, as PGA estimates are comparable with the observed recordings. We also observed that the Fourier spectrum is not a good parameter in deciding the causative fault plane.

  17. Understanding Ground Motion in Las Vegas: Insights from Data Analysis and Two-Dimensional Modeling

    SciTech Connect

    Rodgers, A; Tkalcic, H; McCallen, D

    2004-02-05

    Seismic ground motions are amplified in low velocity sedimentary basins relative to adjacent sites on high velocity hard rock. We used historical recordings of NTS nuclear explosions and earthquake recordings in Las Vegas Valley to quantify frequency-dependent basin amplification using Standard Spectral Ratios. We show that amplifications, referred to as site response, can reach a factor of 10 in the frequency band 0.4-2.0 Hz. Band-averaged site response between 0.4-2.0 Hz is strongly correlated with basin depth. However, it is also well known that site response is related to shallow shear-wave velocity structure. We simulated low frequency (f<1Hz) ground motion and site response with two-dimensional elastic finite difference simulations. We demonstrate that physically plausible models of the shallow subsurface, including low velocity sedimentary structure, can predict relative amplification as well as some of the complexity in the observed waveforms. This study demonstrates that site response can be modeled without invoking complex and computationally expensive three-dimensional structural models.

  18. Empirical relationships between instrumental ground motions and observed intensities for two great Chilean subduction zone earthquakes

    NASA Astrophysics Data System (ADS)

    Cilia, M. G.; Baker, L. M.

    2015-12-01

    We determine empirical relationships between instrumental peak ground motions and observed intensities for two great Chilean subduction earthquakes: the 2010 Mw8.8 Maule earthquake and the 2014 Mw8.2 Iquique earthquake. Both occurred immediately offshore on the primary plate boundary interface between the Nazca and South America plates. They are among the largest earthquakes to be instrumentally recorded; the 2010 Maule event is the second largest earthquake to produce strong motion recordings. Ground motion to intensity conversion equations (GMICEs) are used to reconstruct the distribution of shaking for historical earthquakes by using intensities estimated from contemporary accounts. Most great (M>8) earthquakes, like these, occur within subduction zones, yet few GMICEs exist for subduction earthquakes. It is unclear whether GMICEs developed for active crustal regions, such as California, can be scaled up to the large M of subduction zone events, or if new data sets must be analyzed to develop separate subduction GMICEs. To address this question, we pair instrumental peak ground motions, both acceleration (PGA) and velocity (PGV), with intensities derived from onsite surveys of earthquake damage made in the weeks after the events and internet-derived felt reports. We fit a linear predictive equation between the geometric mean of the maximum PGA or PGV of the two horizontal components and intensity, using linear least squares. We use a weighting scheme to express the uncertainty of the pairings based on a station's proximity to the nearest intensity observation. The intensity data derived from the onsite surveys is a complete, high-quality investigation of the earthquake damage. We perform the computations using both the survey data and community decimal intensities (CDI) calculated from felt reports volunteered by citizens (USGS "Did You Feel It", DYFI) and compare the results. We compare the GMICEs we developed to the most widely used GMICEs from California and

  19. User manual for the NTS ground motion data base retrieval program: ntsgm

    SciTech Connect

    App, F.N.; Tunnell, T.W.

    1994-05-01

    The NTS (Nevada Test Site) Ground Motion Data Base is composed of strong motion data recorded during the normal execution of the US underground test program. It contains surface, subsurface, and structure motion data as digitized waveforms. Currently the data base contains information from 148 underground explosions. This represents about 4,200 measurements and nearly 12,000 individual digitized waveforms. Most of the data was acquired by Los Alamos National Laboratory (LANL) in connection with LANL sponsored underground tests. Some was acquired by Los Alamos on tests conducted by the Defense Nuclear Agency (DNA) and Lawrence Livermore National Laboratory (LLNL), and there are some measurements that were acquired by the other test sponsors on their events and provided for inclusion in this data base. Data acquisition, creation of the data base, and development of the data base retrieval program (ntsgm) are the result of work in support of the Los Alamos Field Test Office and the Office of Nonproliferation and Arms Control.

  20. Strong Ground Motion Simulation of the 2008 MS 8.0 Wenchuan, China, Earthquake

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Yao, X.; Yu, X.

    2014-12-01

    The near source strong ground motions of the 2008 MS 8.0 Wenchuan, China, earthquake are simulated using empirical Green's function (EFG) method. At first, we estimate the locations of strong motion generation areas (SMGA) based on the teleseismic data inversion results by some other researchers. Then, preliminarily determine the total areas of SMGA referring to the scaling law introduced by Somerville et al. (1999). Finally, we implement the genetic algorithm searching for the optimized source parameters. Based on the source models, we synthetize the waveforms for the 18 stations located near the source region. Our results show that the comparison between the synthetic waveforms and the observed records agree each other very well. We find that there are five obvious SMGAs on the fault. The locations of the two of them are similar with the asperities from the teleseismic data inversion. However, the combined strong motion generation areas and the rise time we obtained are smaller than those values predicted by the extension value of the scaling law by Somerville et al. (1999).

  1. Numerical Benchmark of 3D Ground Motion Simulation in the Alpine valley of Grenoble, France.

    NASA Astrophysics Data System (ADS)

    Tsuno, S.; Chaljub, E.; Cornou, C.; Bard, P.

    2006-12-01

    Thank to the use of sophisticated numerical methods and to the access to increasing computational resources, our predictions of strong ground motion become more and more realistic and need to be carefully compared. We report our effort of benchmarking numerical methods of ground motion simulation in the case of the valley of Grenoble in the French Alps. The Grenoble valley is typical of a moderate seismicity area where strong site effects occur. The benchmark consisted in computing the seismic response of the `Y'-shaped Grenoble valley to (i) two local earthquakes (Ml<=3) for which recordings were avalaible; and (ii) two local hypothetical events (Mw=6) occuring on the so-called Belledonne Border Fault (BBF) [1]. A free-style prediction was also proposed, in which participants were allowed to vary the source and/or the model parameters and were asked to provide the resulting uncertainty in their estimation of ground motion. We received a total of 18 contributions from 14 different groups; 7 of these use 3D methods, among which 3 could handle surface topography, the other half comprises predictions based upon 1D (2 contributions), 2D (4 contributions) and empirical Green's function (EGF) (3 contributions) methods. Maximal frequency analysed ranged between 2.5 Hz for 3D calculations and 40 Hz for EGF predictions. We present a detailed comparison of the different predictions using raw indicators (e.g. peak values of ground velocity and acceleration, Fourier spectra, site over reference spectral ratios, ...) as well as sophisticated misfit criteria based upon previous works [2,3]. We further discuss the variability in estimating the importance of particular effects such as non-linear rheology, or surface topography. References: [1] Thouvenot F. et al., The Belledonne Border Fault: identification of an active seismic strike-slip fault in the western Alps, Geophys. J. Int., 155 (1), p. 174-192, 2003. [2] Anderson J., Quantitative measure of the goodness-of-fit of

  2. Simulation of strong ground motion for moderate earthquakes: comparison between two high frequency approaches

    NASA Astrophysics Data System (ADS)

    Emolo, A.; Pacor, F.; Cultrera, G.; Franceschina, G.; Zollo, A.; Cocco, M.

    2003-04-01

    We used two different strong ground motion simulation techniques to generate shaking scenarios for the 1997 Colfiorito earthquake (Mw=6.0). This earthquake has been studied in the framework of a Italian research project (supported by Gruppo Nazionale per la Difesa dai Terremoti - INGV, 2002-2003). The project concerns the design of ground shaking scenarios based on the identification of the position, geometry and rupture mechanism of seismogenetic faults and on the characterization of the crustal structure. Both techniques use the high frequency solution (ray theory) to compute the Green functions in a flat-layered velocity model. While one method (ASymptotic Method, ASM) solves numerically the representation integral, the other one (Deterministic-Stochastic Method, DSM) generalizes the point-source stochastic method using a deterministic acceleration envelope for an extended fault. Only the direct S wave field is computed because, in the near source range, it can be considered dominant in amplitude with respect to the P wave field and secondary phases. We computed synthetic time histories at 64 nodes of a grid area (60km x 60km) up to fmax=5 Hz. First of all, we compared the methods for two source models obtained, for the Colfioririto earthquake, by the inversion of geodetic and accelerometric data. Both techniques give similar distribution of PGA and integral ground motion parameters. In particular, peak values are not symmetrically distributed around the fault, but show the largest amplitude values north to the Colfiorito fault, in the directive direction. The reliability of the proposed rupture scenario has been checked for 6 accelerometric stations located at epicentral distances ranging from 5 to 30 Km that recorded the mainshock. We then generated shaking scenarios varying several parameters, such as the nucleation position, the slip distribution and the rupture velocity. Fault geometry, source mechanism and propagation medium are fixed. The results of the

  3. The January 26, 2001 Mw7.6 Bhuj, India, Earthquake: Observed and Predicted Ground Motions

    NASA Astrophysics Data System (ADS)

    Hough, S. E.; Martin, S.; Bilham, R.; Atkinson, G. M.

    2001-12-01

    It is unclear whether or not the 26 January, 2001, Bhuj earthquake occurred in an intraplate or interplate setting. However, to understand the damage caused by this earthquake, and the hazard posed by future similar earthquakes, one must consider not only the source setting but propagation issues as well. Although local and regional instrumental recordings of the devastating January 26, 2001, Bhuj earthquake are sparse, the distribution of macroseismic effects can provide constraints on the ground motions. We compiled news accounts describing damage and other effects and interpreted them to obtain modified Mercalli intensities at over 300 locations throughout the Indian subcontinent. These values are used to map the intensity distribution using a simple mathematical interpolation method. These maps reveal several interesting features. Significant sediment-induced amplification is suggested at a number of locations around the Gulf of Kachchh and in other areas along rivers, within deltas, or on coastal alluvium. The overall distribution of intensities also reveals extremely efficient wave propagation throughout the subcontinent: the earthquake was felt at distances as large as 2400 km and caused light damage at distances upwards of 700 km. This is consistent with earlier theoretical and observational results suggesting that higher mode surface waves (Lg waves) will propagate efficiently in intraplate crust, which forms a relatively uniform, high-Q waveguide. We use fault rupture parameters inferred from teleseismic data to predict ground motions at distances of 0-1000 km. We convert the predicted peak ground acceleration (PGA) values to MMI using a relationship between MMI and PGA that assigns MMI based on the average effects in a region. The predicted MMI's are typically lower by 1-2 units than the estimated values. We discuss two factors that probably account for this discrepancy: 1) a tendency for media accounts to focus on the most dramatic damage, rather than

  4. Analysis of Recorded and Simulated Far-Field Ground Motion From the Source Physics Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Pitarka, A.; Mellors, R. J.; Vorobiev, O. Y.; Rodgers, A. J.; Walter, W. R.; Antoun, T.; Matzel, E.; Ford, S. R.; Wagoner, J. L.; Petersson, A.; Sjogreen, B.

    2013-12-01

    The Source Physics Experiment (SPE) provides new data for investigating the excitation and propagation of seismic waves generated by buried explosions. The main subjects of our ongoing investigation are the generation of shear-waves, propagation of seismic energy at local and regional distances, and development of numerical techniques for simulating ground motion from underground explosions using physics based source models for different emplacement conditions. We will present an overview of our investigation results based on analysis of far-field waveforms recorded by five linear arrays of stations within 10 km of the shot point, and a small array of stations, with a 2km epicentral distance. We tested the efficiency of our numerical scheme that uses three-dimensional hydrodynamic methods, coupled with an anelastic wave propagation finite-difference method to model the explosion source and ground motion recorded at far-field stations. The best source models that fit the recorded shear and compressional near-field motion, and a calibrated 3D local velocity model, were used to evaluate the sensitivity of wave propagation near the source region to source process, including spall, underground structure, high frequency wave scattering, and surface topography. In particular, we focused on the contribution of these effects to S-wave generation and P/S amplitude ratio in the modeled frequency range of 0.1-8Hz. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  5. Single-Station Strong Ground-Motion Relationship for North Eastern Taiwan Subduction Zone Earthquakes

    NASA Astrophysics Data System (ADS)

    Yeh, Ting-Yu; Lee, Chyi-Tyi

    2016-04-01

    Sigma (standard deviation) of ground-motion prediction equation (GMPE) has great impact on probabilistic seismic hazard analysis (PSHA). Therefore, how to properly evaluate the sigma has been a crucial issue currently. It is very suitable for seismic-related research due to the abundant earthquake data in Taiwan. With establishing single-station GMPE, the sigma can be reduced due to eliminating the variance from site effect. In this study, ground-motion data of subduction zone for both interface and intraslab earthquakes are obtained from the Taiwan Strong-Motion Instrumentation Program (TSMIP). A total of 174 earthquakes and 14,551 records which moment magnitude greater than 4.0 are selected to establish PGA attenuation relationship. We chose the general usage of the functional forms by reviewing of previous studies. Each candidate term in the form was tested with Taiwan data set. The final form is generally similar to the form proposed by Lin and Lee (2008), besides a quadratic magnitude term, a VS30 term and a focal mechanism term were added. The coefficients of the equation are determined through non-linear regression analysis using maximum likelihood method (MLE) and mixed-effects model. Both regional GMPE and 44 single-station GMPEs are done in this study. The results show that intraslab earthquakes generaly predict higher PGA than that of interface earthquakes. Comparing the sigma of regional GMPE and single-station GMPEs, the single-station sigmas are smaller than the regional sigma with a reduction rate from 1.5% to 37.0%, averaging 21.7%.

  6. Strong Ground Motion Simulation of the 2011 Honshu, Japan, Earthquake Using Empirical Green's Function

    NASA Astrophysics Data System (ADS)

    Yao, X.; Zhang, W.

    2011-12-01

    The Mw 9.0 Honshu earthquake of March 11, 2011 is the largest earthquake ever recorded in Japan, and is among the 5 largest earthquakes recorded worldwide. It has been followed by a series of powerful aftershocks, with 31 events of magnitude larger than 6 in three days. It generated huge tsunami waves in the Pacific. The death toll as of April 2, 2011 exceeded 12,157 largely due to the tsunami whose amplitude overwhelmed coastal defences. In this study, we simulate the near-field strong ground motions of this earthquake by using empirical Green's function (EGF) method (Irikura, 1988) .Slip-distribution inversion results from USGS, ERI, etc. showed that there were two large asperities on the fault plane. According to these results, we selected two aftershocks whose source mechanisms were similar with the two asperities as the EGFs. Considering the epicenter distance of all selected stations is less than the fault dimension of the 2011 Honshu Earthquake, we did not estimate the parameter of EGF (C and N) by the source spectral fitting method, but directly applied the scaling relation (Somerville et al., 1999) to estimate the size of strong motion generation area (SMGA) in the rupture area of the main-shock, and then use the genetic algorithm (GA) to get the best values of the parameter of C (related the stress drop) and the source rise-time by fitting the envelope of the synthetic broadband waveforms with that of the observed records. Based on the source model, we simulated the near-field strong ground motions. Our result shows that most of the syntheti waveforms agreed well with the observed records in the frequency range from 0.5 Hz to 10 Hz. Our result also shows that the source rise-time we obtained is smaller than the extrapolation of the scaling law proposed by Somerville et al. (1999).

  7. Regional-specific Stochastic Simulation of Spatially-distributed Ground-motion Time Histories using Wavelet Packet Analysis

    NASA Astrophysics Data System (ADS)

    Huang, D.; Wang, G.

    2014-12-01

    Stochastic simulation of spatially distributed ground-motion time histories is important for performance-based earthquake design of geographically distributed systems. In this study, we develop a novel technique to stochastically simulate regionalized ground-motion time histories using wavelet packet analysis. First, a transient acceleration time history is characterized by wavelet-packet parameters proposed by Yamamoto and Baker (2013). The wavelet-packet parameters fully characterize ground-motion time histories in terms of energy content, time- frequency-domain characteristics and time-frequency nonstationarity. This study further investigates the spatial cross-correlations of wavelet-packet parameters based on geostatistical analysis of 1500 regionalized ground motion data from eight well-recorded earthquakes in California, Mexico, Japan and Taiwan. The linear model of coregionalization (LMC) is used to develop a permissible spatial cross-correlation model for each parameter group. The geostatistical analysis of ground-motion data from different regions reveals significant dependence of the LMC structure on regional site conditions, which can be characterized by the correlation range of Vs30 in each region. In general, the spatial correlation and cross-correlation of wavelet-packet parameters are stronger if the site condition is more homogeneous. Using the regional-specific spatial cross-correlation model and cokriging technique, wavelet packet parameters at unmeasured locations can be best estimated, and regionalized ground-motion time histories can be synthesized. Case studies and blind tests demonstrated that the simulated ground motions generally agree well with the actual recorded data, if the influence of regional-site conditions is considered. The developed method has great potential to be used in computational-based seismic analysis and loss estimation in a regional scale.

  8. The Dependence of High-Frequency Characteristics of Ground Motion on Rupture-Model Parameters

    NASA Astrophysics Data System (ADS)

    Erickson, B. A.; Shi, Z.; Day, S. M.

    2013-12-01

    Recent 3-D numerical simulations reveal that high-frequency ground motion generated from rupture propagation on rough faults is influenced by the properties of fault roughness, frictional parameters, and off-fault plastic response. In particular, the predicted Fourier spectra of ground acceleration from rupture along faults with self-similar roughness are roughly flat between a few tenths of a Hz and a source-controlled upper cutoff frequency. Fourier spectra of recorded ground motion exhibit a similar upper cutoff frequency, conventionally called f_max, which appears to be principally controlled by path and site attenuation. An open question is the extent to which the path and site effects overprint a source-controlled contribution to f_max such as that found in the numerical simulations. As a step toward addressing that question, we refine the theoretical predictions by further examining the sensitivity of source f_max to rupture model parameters. Initial findings from our earlier 3-D simulations (Shi and Day, 2013) have identified three key sensitivities: a downward shift of source f_max occurs when (i) the off-fault material undergoes plastic deformation (relative to the corresponding elastic simulations); (ii) the minimum roughness wavelength of the fault profile is increased; and/or (iii) the state evolution distance in the friction law is increased. These effects are both nonlinear and strongly coupled to each other. In this work, we perform a more extensive parametric study with 2-D rough-fault simulations to examine the aforementioned f_max sensitivity factors, their scaling with event magnitude and roughness amplitude, and their dependence on the plastic yielding parameters.

  9. Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion

    NASA Astrophysics Data System (ADS)

    Hirata, N.; Sato, H.; Koketsu, K.; Umeda, Y.; Iwata, T.; Kasahara, K.

    2003-12-01

    Introduction: After the 1995 Kobe earthquake, the Japanese government increased its focus and funding of earthquake hazards evaluation, studies of man-made structures integrity, and emergency response planning in the major urban centers. A new agency, the Ministry of Education, Science, Sports and Culture (MEXT) has started a five-year program titled as Special Project for Earthquake Disaster Mitigation in Urban Areas (abbreviated to Dai-dai-toku in Japanese) since 2002. The project includes four programs: I. Regional characterization of the crust in metropolitan areas for prediction of strong ground motion. II. Significant improvement of seismic performance of structure. III. Advanced disaster management system. IV. Investigation of earthquake disaster mitigation research results. We will present the results from the first program conducted in 2002 and 2003. Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion: A long-term goal is to produce map of reliable estimations of strong ground motion. This requires accurate determination of ground motion response, which includes a source process, an effect of propagation path, and near surface response. The new five-year project was aimed to characterize the "source" and "propagation path" in the Kanto (Tokyo) region and Kinki (Osaka) region. The 1923 Kanto Earthquake is one of the important targets to be addressed in the project. The proximity of the Pacific and Philippine Sea subducting plates requires study of the relationship between earthquakes and regional tectonics. This project focuses on identification and geometry of: 1) Source faults, 2) Subducting plates and mega-thrust faults, 3) Crustal structure, 4) Seismogenic zone, 5) Sedimentary basins, 6) 3D velocity properties We have conducted a series of seismic reflection and refraction experiment in the Kanto region. In 2002 we have completed to deploy seismic profiling lines in the Boso peninsula (112 km) and the

  10. Sampling of Stochastic Input Parameters for Rockfall Calculations and for Structural Response Calculations Under Vibratory Ground Motion

    SciTech Connect

    M. Gross

    2004-09-01

    The purpose of this scientific analysis is to define the sampled values of stochastic (random) input parameters for (1) rockfall calculations in the lithophysal and nonlithophysal zones under vibratory ground motions, and (2) structural response calculations for the drip shield and waste package under vibratory ground motions. This analysis supplies: (1) Sampled values of ground motion time history and synthetic fracture pattern for analysis of rockfall in emplacement drifts in nonlithophysal rock (Section 6.3 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (2) Sampled values of ground motion time history and rock mechanical properties category for analysis of rockfall in emplacement drifts in lithophysal rock (Section 6.4 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (3) Sampled values of ground motion time history and metal to metal and metal to rock friction coefficient for analysis of waste package and drip shield damage to vibratory motion in ''Structural Calculations of Waste Package Exposed to Vibratory Ground Motion'' (BSC 2004 [DIRS 167083]) and in ''Structural Calculations of Drip Shield Exposed to Vibratory Ground Motion'' (BSC 2003 [DIRS 163425]). The sampled values are indices representing the number of ground motion time histories, number of fracture patterns and rock mass properties categories. These indices are translated into actual values within the respective analysis and model reports or calculations. This report identifies the uncertain parameters and documents the sampled values for these parameters. The sampled values are determined by GoldSim V6.04.007 [DIRS 151202] calculations using appropriate distribution types and parameter ranges. No software development or model development was required for these calculations. The calculation of the sampled values allows parameter uncertainty to be incorporated into the rockfall and structural response calculations that support development of the seismic scenario for the

  11. Strong ground motion synthesis along the Sanyi-Tungshih-Puli seismic zone using empirical Green`s functions

    SciTech Connect

    Hutchings, L.; Foxall, W.; Kasameyer, P.; Wu, F.T.; Rau, R.-J.; Jarpe, S.

    1997-01-01

    We synthesize strong ground motion from a M=7.25 earthquake along the NW-trending Sanyi-Tungshih-Puli seismic zone. This trend extends from Houlong to Taichung and forms a nearly continuous 78 km long seismic zone identified by the occurrence of M<5 events. It extends from a shallow depth all the way down to about 40 km. The entire length of the fault, if activated at one time, can lead to an event comparable to that the 1995 Kobe earthquake. With the improved digital CWBSN data now provided routinely by CWBSN, it becomes possible to use these data as empirical Green`s functions to synthesize potential ground motion for future large earthquakes. We developed a suite of 100 rupture scenarios for the earthquake and computed the commensurate strong ground motion time histories. We synthesized strong ground motion with physics-based solutions of earthquake rupture and applied physical bounds on rupture parameters. the synthesized ground motions obtained for a fixed magnitude and identifying the hazard to a site from the statistical distribution of engineering parameters, we have introduced a probabilistic component to the deterministic hazard calculation, The time histories suggested for engineering design are the ones that most closely match either the average or one standard deviation absolute acceleration response values.

  12. Characterizing long period (1--10 sec) ground motions for base isolated structures located in sedimentary basins

    SciTech Connect

    Graves, R.W.; Somerville, P.G.

    1995-12-01

    Many urban regions, including Los Angeles, Portland and Seattle in the United States and Tokyo in Japan, are located above deep sedimentary basins. The conventional approach of estimating ground motions in these environments is to assume that the geology can be characterized by a horizontally stratified medium, and that only the shallowest few tens of meters influence the ground motion characteristics. However, the trapping and amplification of long period (1-10 sec) waves by sedimentary basins can generate amplitudes that are significantly larger than those calculated from simple 1D models of site resonance. This may be of particular concern for base isolated structures which are most sensitive to ground motions in this period range. The recent development of efficient computational methods for modeling seismic wave, propagation in laterally varying geological structure enable the authors to model the effects of sedimentary basins on earthquake generated ground motions. They are now applying this calculation procedure to characterize the ground motions that may be generated in the Puget Trough and the Portland Basin due to large earthquakes on the Cascadia subduction zone, and in the Los Angeles region due to large earthquakes on blind thrust faults beneath the Los Angeles basin.

  13. Preliminary ground motion prediction equations for the Central and Eastern United States

    NASA Astrophysics Data System (ADS)

    Graizer, V.

    2014-12-01

    At the current stage I used the database created under the Next Generation Attenuations (NGA-East) project by Cramer et al. (2013). In contrast to the active tectonic environment in the Western US (WUS) the strong motion record database for the stable continental environment in the Central and Eastern US (CEUS) is not sufficient to create purely empirical ground motion prediction equations (GMPE) covering required for the PSHA magnitude (4.5ground acceleration (PGA) was composed of five different filters. For consistency I keep same number of filters for the CEUS GMPE. The main filter modeling the distance attenuation of ground-motion is similar to the frequency response function of a damped single-degree-of-freedom oscillator with frequency replaced by distance to the fault. Following the approach developed in Graizer and Kalkan (2009) for WUS spectral acceleration (SA) prediction model explicitly integrates PGA as a scaling factor for the spectral shape, which is a continuous function of spectral period. Geometrical spreading of R-1 combined with anelastic attenuation Q0 is used allowing adjusting the model for

  14. Ground motion measurement in the lake Mead (Nevada, USA) area by temporal analysis of multiple interferograms.

    NASA Astrophysics Data System (ADS)

    Cavalie, O.; Doin, M.; Lasserre, C.; Briole, P.

    2004-12-01

    SAR interferometry has proven to be a reliable method for detecting small displacements due to ground subsidence. In this study, we propose to measure ground motion around the lake Mead (Nevada, USA) using InSAR. This artificial lake has been filled with water in 1935. An earlier studie, based on levelling measurements, has shown that the lake impoundement has induced a subsidence of 17 centimeters (Kaufmann et al., 2000). This relaxation process is analogous to the postglacial rebound, but at a smaller scale. To quantify the deformation and constrain the crust and mantle rheological parameters in the lake area, we have analysed multiple interferograms (245) based on 45 ERS images between 1992 and 2001. The interferometric phase contains information about deformation occurring between two satellite passes, as well as satellite orbits errors, topographic, and atmospheric artefacts. The topographic signature is removed using the 3-arc seconds SRTM data. To correct for orbital errors, we remove a best fitting linear ramp. Atmospheric artefact, in our interferograms, are mainly due to the variation of water vapor vertical stratification between the two passes. This results in a interferometric phase correlation with altitude which we remove by minimization. These corrections are then refined through an iterative procedure and validated using data from global atmospheric models. Corrected interferograms are then inverted to solve for deformation using a method based on the large spatial coverage of coherent pixels, allowing to strengthen the signal to noise ratio (Schmidt and Burgmann, 2003). This data inversion provides a time series of the expected deformation in the lake Mead area. The analysis of the deformation evolution during the period covered by the ERS satellites (1992-2001) shows a correlation between the vertical motion and the water level changes. So, we observe a subsidence of up to 1.5 cm between 1996 and 1998, followed by an uplift due to the drop of the

  15. The SCEC-USGS Dynamic Earthquake Rupture Code Verification Exercise: Regular and Extreme Ground Motion

    NASA Astrophysics Data System (ADS)

    Harris, R.; Barall, M.; Archuleta, R. J.; Aagaard, B.; Ampuero, J. P.; Andrews, D. J.; Cruz-Atienza, V. M.; Dalguer Gudiel, L. A.; Day, S. M.; Duan, B.; Dunham, E. M.; Ely, G. P.; Gabriel, A. A.; Kaneko, Y.; Kase, Y.; Lapusta, N.; Ma, S.; Noda, H.; Oglesby, D. D.; Olsen, K. B.; Roten, D.; Song, S.

    2010-12-01

    We summarize recent progress by the SCEC-USGS Dynamic Rupture Code Verification Group, that examines if SCEC and USGS researchers’ spontaneous-rupture computer codes agree when computing benchmark scenarios for dynamic earthquake rupture. Our latest benchmarks are ‘regular’ dynamic ruptures on a vertical strike-slip fault and on a normal fault, at a range of resolutions, and, ‘extreme’ dynamic ruptures on a normal fault. The ‘extreme’ dynamic ruptures were designed as complete stress-drop, supershear ruptures that would be most likely to produce maximum possible ground motions. These simulated ruptures could be thought of as very unlikely, but still possible. Among the 2009 ‘extreme’ dynamic rupture benchmarks were those targeted to test two simplified versions of the Andrews et al. [BSSA, 2007] numerical simulations for hypothesized maximum-possible ground motion at a site near Yucca Mountain. To test the Andrews et al. methodology, we constructed a benchmark for a planar dipping normal-fault set in a medium where the off-fault response was designated to be elastic (TPV12), and another benchmark where the off-fault response was designated to be plastic (TPV13). Although most of our group’s previous benchmarks have concentrated on 3D solutions, both the TPV12 and TPV13 benchmarks were offered with both 2D and 3D options, partly because the Andrews et al. study was conducted in 2D, and partly because it is important to understand the differences and similarities among 2D and 3D rupture propagation and ground motion predictions. Seven researchers’ codes participated in the TPV12 2D benchmark test, seven participated in the TPV12 3D test, six participated in the TPV13 2D benchmark test, and four participated in the TPV13 3D test. Our findings were similar to those hypothesized in the Andrews et al. publication. At a proposed site for a nuclear waste repository, that was modeled to be 1-km from the fault, at 300 m depth, our 2D elastic benchmark

  16. Ground Motion Scaling in Kachchh: a Preliminary Assessment from Aftershocks of the 2001 Bhuj, India, Earthquake

    NASA Astrophysics Data System (ADS)

    Bodin, P.; Malagnini, L.; Akinci, A.

    2002-12-01

    Considerable controversy surrounds the issues of how much and how systematically source and propagation characteristics of earthquakes that take place in relatively "stable" continental settings differ from those of earthquakes in more mobile crust. The 2001 Mw 7.7 Bhuj, India, earthquake may have been the largest such earthquake in more than 100 years. We are analyzing ground motions from aftershocks of the Bhuj earthquake recorded on a temporary network deployed within 100 km of the mainshock epicenter. Our goal is to determine the source and propagation characteristics in the region, taking into account site effects at our network sites, to facilitate comparison with similar studies in other tectonic environments. To date we have used data from about 1100 earthquakes ranging in magnitude from about 2 to about 5 1/2. We model peak amplitudes as a function of source-receiver distance for bandpass-filtered time series and the spectral amplitudes of time-windowed seismograms. Because the earthquakes occurred over a wide depth range, we have analyzed the data in two overlapping depth subsets-shallower than 25 km and deeper than 20 km. We find that propagation is well-modeled by a frequency-dependent quality factor Q = 680f0.48 combined with a rather simple geometric spreading function that varies only slightly between the deep and shallow data subsets. We modeled the source terms with an w2 single corner (Brune) model with a magnitude dependent stress drop. The larger earthquakes had stress drops of about 160 bars. Extrapolating our source and propagation values using Random Vibration Theory to an Mw 7.5 earthquake yields ground motion estimates that coincide closely with similar current estimates for eastern North America (ENA) earthquakes. Our preliminary assessment is that, from a ground motion perspective, the Bhuj earthquake presents an important opportunity to study an earthquake that (a) differs significantly from earthquakes in mobile crust, and (b) resembles

  17. Report of Earthquake Drills with Experiences of Ground Motion in Childcare for Young Children, Japan

    NASA Astrophysics Data System (ADS)

    Yamada, N.

    2013-12-01

    After the Great East Japan Earthquake of 2011, this disaster has become one of the opportunities to raise awareness of earthquake and tsunami disaster prevention, and the improvement of disaster prevention education is to be emphasized. The influences of these bring the extension to the spatial axis in Japan, and also, it is important to make a development of the education with continuous to the expansion of time axes. Although fire or earthquake drills as the disaster prevention education are often found in Japan, the children and teachers only go from school building to outside. Besides, only the shortness of the time to spend for the drill often attracts attention. The complementary practice education by the cooperation with experts such as the firefighting is practiced, but the verification of the effects is not enough, and it is the present conditions that do not advance to the study either. Although it is expected that improvement and development of the disaster prevention educations are accomplished in future, there are a lot of the problems. Our target is construction and utilization of material contributing to the education about "During the strong motion" in case of the earthquake which may experience even if wherever of Japan. One of the our productions is the handicraft shaking table to utilize as teaching tools of the education to protect the body which is not hurt at the time of strong motion. This made much of simplicity than high reproduction of the earthquake ground motions. We aimed to helping the disaster prevention education including not only the education for young children but also for the school staff and their parents. In this report, the focusing on a way of the non-injured during the time of the earthquake ground motion, and adopting activity of the play, we are going to show the example of the framework of earthquake disaster prevention childcare through the virtual experience. This presentation has a discussion as a practice study with

  18. Computation of linear and nonlinear site response for near field ground motion

    NASA Astrophysics Data System (ADS)

    Bonilla, Luis Fabian

    The near-surface geological site conditions in the upper tens of meters are one of the dominant factors in controlling the amplitude and variation of strong ground motion during large earthquakes. The understanding of these site effects comes primarily from surface recordings. For instance, different methods to estimate site response and their variability are studied using aftershock data for the 17 January 1994 M6.7 Northridge, California earthquake. A second approach corresponds to borehole measurements. We use the Garner Valley Downhole Array (GVDA), which consists of a set of seven downhole strong-motion instruments ranging from 0 to 500 meters depth, to study site response effects. The GVDA velocity structure is first studied, then the H/ V is evaluated, and finally some considerations of 2D and 3D basin effects are also shown. These previous studies considered small to moderate earthquakes, where strain levels are small enough, so that linear wave propagation is assumed. However, for strong motions produced during large earthquakes, the soils behave nonlinearly. In this study we present evidence that nonlinearity can be directly observed in acceleration time histories such as Wildlife Refuge, 1987 Superstition Hills, CA; Kushiro Port station, 1993 Kushiro-Oki, Japan; among others. To understand the nature of nonlinear soil dynamics, we developed a model that includes anelastic dissipation of energy due to hysteresis. The hysteresis is described by the generalized Masing rules. This new hysteresis formulation, based on the classical Masing rules, has a functional representation, and depends only on one parameter that can be related to damping ratio tests. The coupling with pore pressure generation shows the degradation of the shear modulus and the yield stress during the cyclic response of the material. The simulations show amplitude reduction as well as the shift of the fundamental frequency to lower frequencies as observed on vertical arrays. The synthetic

  19. Strong ground motion data from the 1983 Borah Peak, Idaho earthquake recorded at the Idaho National Engineering Laboratory

    SciTech Connect

    Jackson, S.M.; Boatwright, J.

    1985-01-01

    The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90 to 110 km. Peak horizontal accelerations (PGA) recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g at ground level to 0.059 g above ground floor level. A temporary array of digital seismographs deployed by the US Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4 to 45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. Two separate analyses were used to estimate near-field ground motion. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of Intensity VII.

  20. Ground Motion Measurement in the Lake Mead Area (Nevada, USA), by Temporal Analysis of Multiple Interferograms.

    NASA Astrophysics Data System (ADS)

    Doin, M.; Cavalie, O.; Lasserre, C.; Briole, P.

    2005-12-01

    SAR interferometry has proven to be a reliable method for detecting small displacements due to ground subsidence. In this study, we measure ground motion around the lake Mead (Nevada, USA) using InSAR. This artificial lake has been filled with water in 1935. An earlier study, based on leveling measurements, has shown that the load associated with lake impoundment has induced a delayed subsidence of 17 centimeters. This relaxation process has been argued to be due to viscous displacement in the uppermost mantle, analogous to the postglacial rebound, but at a smaller spatial scale and with a much lower viscous relaxation scale. To quantify the deformation and thus constrain the crust and mantle rheological parameters in the lake area, we analyse multiple interferograms (~280) based on 43 ERS images acquired between 1992 and 2001 and on 12 Envisat images acquired between 2003 and 2005. ERS-Envisat interferograms are performed to merge the two data sets in one time series. With baselines smaller than 300 m, all interferograms have a very good coherence due to the desert region. Most interferograms show strong atmospheric artefacts that are partly due to the variation of water vapor vertical stratification between two satellite passes. Tropospheric delay is computed for each interferogram using the correlation between phase and elevation far from the lake area. It is then inverted for each date of SAR images before interferograms correction. These corrections are validated using data from global atmospheric models (ERA40). Corrected interferograms are then inverted to solve for time series of the expected deformation in the lake Mead area . The linear inversion treats each pixel independently from its neighbours and use the data redundancy to reduce errors such as local decorrelations. Smoothing constraints added in the inversion efficiently eliminate local atmospheric artefacts. We obtain a time series of the expected deformation in the lake Mead area. The analysis of

  1. A Test of a Strong Ground Motion Prediction Methodology for the 7 September 1999, Mw=6.0 Athens Earthquake

    SciTech Connect

    Hutchings, L; Ioannidou, E; Voulgaris, N; Kalogeras, I; Savy, J; Foxall, W; Stavrakakis, G

    2004-08-06

    We test a methodology to predict the range of ground-motion hazard for a fixed magnitude earthquake along a specific fault or within a specific source volume, and we demonstrate how to incorporate this into probabilistic seismic hazard analyses (PSHA). We modeled ground motion with empirical Green's functions. We tested our methodology with the 7 September 1999, Mw=6.0 Athens earthquake, we: (1) developed constraints on rupture parameters based on prior knowledge of earthquake rupture processes and sources in the region; (2) generated impulsive point shear source empirical Green's functions by deconvolving out the source contribution of M < 4.0 aftershocks; (3) used aftershocks that occurred throughout the area and not necessarily along the fault to be modeled; (4) ran a sufficient number of scenario earthquakes to span the full variability of ground motion possible; (5) found that our distribution of synthesized ground motions span what actually occurred and their distribution is realistically narrow; (6) determined that one of our source models generates records that match observed time histories well; (7) found that certain combinations of rupture parameters produced ''extreme'' ground motions at some stations; (8) identified that the ''best fitting'' rupture models occurred in the vicinity of 38.05{sup o} N 23.60{sup o} W with center of rupture near 12 km, and near unilateral rupture towards the areas of high damage, and this is consistent with independent investigations; and (9) synthesized strong motion records in high damage areas for which records from the earthquake were not recorded. We then developed a demonstration PSHA for a source region near Athens utilizing synthesized ground motion rather that traditional attenuation. We synthesized 500 earthquakes distributed throughout the source zone likely to have Mw=6.0 earthquakes near Athens. We assumed an average return period of 1000 years for this magnitude earthquake in the particular source zone

  2. Ground motion analyses: OSSY (a high explosive experiment) and MERLIN (a nuclear event)

    SciTech Connect

    Swift, R.P.

    1991-10-01

    We have analyzed recorded data and conducted numerical simulations of the seismic-calibration high explosive experiment OSSY and of the underground nuclear event MERLIN to determine if there is any physical correlation in their ground motion response. Waveforms recorded on OSSY and MERLIN show a distinct similarity in the form of a dual-pulse structure, with the second pulse as large or larger than the first pulse. Results with 1D and 2D simulations show that there is no correlation. The dual-pulse structure for OSSY can best be accounted for by a dilatancy feature resulting from pore recovery during unloading. There is also a notable influence on the pulse shape caused by the large length-to-diameter ratio of the high explosive charge. The dual-pulse structure recorded in MERLIN is most likely due to refraction from a higher-impedance layer about 60 m below the workout. 15 refs., 26 figs.

  3. Analysis spectral shapes from California and central United States ground motion

    SciTech Connect

    Not Available

    1994-01-24

    The objective of this study is to analyze the spectral shapes from earthquake records with magnitudes and distances comparable to those that dominate seismic hazard at Oak Ridge, in order to provide guidance for the selection of site-specific design-spectrum shapes for use in Oak Ridge. The authors rely heavily on California records because the number of relevant records from the central and eastern United States (CEUS) is not large enough for drawing statistically significant conclusions. They focus on the 0.5 to 10-Hz frequency range for two reasons: (1) this is the frequency range of most engineering interest, and (2) they avoid the effect of well-known differences in the high-frequency energy content between California and CEUS ground motions.

  4. Spectral characteristics of vertical ground motion in the Northridge and other earthquakes

    SciTech Connect

    Bozorgnia, Y.; Niazi, M.; Campbell, K.W.

    1995-12-31

    Spectral characteristics of vertical ground motion recorded during the Northridge earthquake are evaluated and compared to those of other earthquakes. Relationship between vertical and horizontal spectra is examined through development of attenuation of vertical and horizontal response spectra. Vertical-to-horizontal response spectral relationship is then compared to that of 1989 Loma Prieta earthquake, and several other earthquakes recorded over SMART-1 array in Taiwan. This preliminary analysis shows that the main characteristics of vertical-to-horizontal spectral ratio are similar to those of other earthquakes. One main characteristic is that in the near-field region and in short period range, the ratio is much higher than commonly assumed ratio of 2/3.

  5. Extreme Ground Motion Recorded in the Near-Source Region of Underground Nuclear Explosions

    SciTech Connect

    Foxall, W

    2005-01-04

    Free-field recordings of underground nuclear explosions constitute a unique data set within the near-source region of seismic events ranging in magnitude from M3 to M6.5. The term ''free-field'' in this context refers to recordings from instruments emplaced in boreholes or tunnel walls such that the initial portions of the records ({approx}0.1 to 1 second) do not contain effects resulting from reflections at the free surface. In addition to the free-field instruments deployed to record ground motions from selected underground nuclear explosions at the Nevada Test Site (NTS) and elsewhere, surface arrays were routinely deployed to record surface accelerations and velocities from underground nuclear tests conducted at NTS.

  6. Velocity and Density Models Incorporating the Cascadia Subduction Zone for 3D Earthquake Ground Motion Simulations

    USGS Publications Warehouse

    Stephenson, William J.

    2007-01-01

    INTRODUCTION In support of earthquake hazards and ground motion studies in the Pacific Northwest, three-dimensional P- and S-wave velocity (3D Vp and Vs) and density (3D rho) models incorporating the Cascadia subduction zone have been developed for the region encompassed from about 40.2?N to 50?N latitude, and from about -122?W to -129?W longitude. The model volume includes elevations from 0 km to 60 km (elevation is opposite of depth in model coordinates). Stephenson and Frankel (2003) presented preliminary ground motion simulations valid up to 0.1 Hz using an earlier version of these models. The version of the model volume described here includes more structural and geophysical detail, particularly in the Puget Lowland as required for scenario earthquake simulations in the development of the Seattle Urban Hazards Maps (Frankel and others, 2007). Olsen and others (in press) used the model volume discussed here to perform a Cascadia simulation up to 0.5 Hz using a Sumatra-Andaman Islands rupture history. As research from the EarthScope Program (http://www.earthscope.org) is published, a wealth of important detail can be added to these model volumes, particularly to depths of the upper-mantle. However, at the time of development for this model version, no EarthScope-specific results were incorporated. This report is intended to be a reference for colleagues and associates who have used or are planning to use this preliminary model in their research. To this end, it is intended that these models will be considered a beginning template for a community velocity model of the Cascadia region as more data and results become available.

  7. Variation of Horizontal Ground Motion Polarization across the Pernicana Fault, Mt. Etna

    NASA Astrophysics Data System (ADS)

    Pischiutta, M.; Salvini, F.; Rovelli, A.

    2011-12-01

    Across the trace of the Pernicana fault on Mt. Etna, a strong polarization of horizontal ground motion was observed in previous studies, at several tens of stations and both on ambient noise and earthquake records. This polarization showed a persistent variation in the polarization angle when moving from the fault hangingwall to the fault footwall. In this work we propose an interpretation of this variation, calculating the brittle deformation pattern associated to the fault through the package FRAP3. Our hypothesis is that ground motion horizontal polarization in fault zones is produced by the brittle deformation fields in the damage zone, with a predominant near-perpendicular relation between fractures and polarization angles. We modeled the fracture field expected for the Pernicana fault system in the Piano Pernicana sector. We assumed a pure left-lateral kinematics in the hanging wall, while in the footwall that is part of the flank instability we added a slight transtensive component to the strike-slip movement. As a result, in the fault hanging wall the synthetic cleavage has a higher probability to develop, with an orientation toward N75 direction. Meanwhile, the extensional fractures appear to be the dominating fracture systems in the fault footwall, with a modeled N40 orientation. As a consequence, we ascribe the variation in polarization azimuth to the distribution of the fracture systems, which appears to be different in the hangingwall and in the footwall. Consistently with previous studies, a near-perpendicular relation between wave polarization and the dominant fracture field is recognized on the Pernicana fault, due to the reduction of rock stiffness caused by the presence of fractures: horizontal vibrations are far more pronounced in the direction perpendicular to fractures.

  8. Empirical evidence of Rayleigh waves in Norcia (central Italy) and their quantitative contribution to ground motion

    NASA Astrophysics Data System (ADS)

    Caffagni, Enrico; Cattaneo, Marco; Bordoni, Paola

    2016-04-01

    Spectral ratio techniques, such as the Horizontal-to-Vertical (HV) and Standard (SSR) may exhibit different trends in specific frequency bands when conducted in alluvial basins. A possible explanation of this discrepancy can be provided by the presence of Rayleigh oscillations, that are considered responsible of an amplification of the vertical component with respect to the horizontal. We propose a new methodology for the identification of Rayleigh waves arrivals, to test on small-size basins. With this procedure, candidate Rayleigh waves are localized in time-frequency domain on an instantaneous polarization plane which is constructed by defining the instantaneous maximum vertical and horizontal spectral amplitudes. Validation of the candidate Rayleigh arrivals is performed by evaluating the instantaneous ellipticity. This step yields to a quantitative measure of the polarization, providing an indicator of the Rayleigh contribution to ground motion. We tested this methodology in the Norcia basin (central Italy) using a 18 selected earthquakes (2.0 < Ml < 5.0) dataset which included seismic events recorded from the L'Aquila sequence (2009). We demonstrate the robustness of our methodology by localizing evidences of Rayleigh wave arrivals immediately from (1 s) up to 30 s after the first S-wave group, even for low-magnitude events (Ml < 3.0). The generation of the detected Rayleigh waves analyzed in time-frequency range, appears to be magnitude-dependent and in function of the location in the basin. Our quantitative estimate of the Rayleigh polarization resulted to be comparable to the HV response value in specific frequency bands, for example in deamplification, demonstrating a plausible connection with Rayleigh oscillations. The authors encourage the usage or implementation of similar procedures conducted in basin studies, in order to determine quantitatively the Rayleigh contribution to ground motion, for a better characterization of the local seismic response.

  9. Deconvolution effect of near-fault earthquake ground motions on stochastic dynamic response of tunnel-soil deposit interaction systems

    NASA Astrophysics Data System (ADS)

    Hacıefendioğlu, K.

    2012-04-01

    The deconvolution effect of the near-fault earthquake ground motions on the stochastic dynamic response of tunnel-soil deposit interaction systems are investigated by using the finite element method. Two different earthquake input mechanisms are used to consider the deconvolution effects in the analyses: the standard rigid-base input and the deconvolved-base-rock input model. The Bolu tunnel in Turkey is chosen as a numerical example. As near-fault ground motions, 1999 Kocaeli earthquake ground motion is selected. The interface finite elements are used between tunnel and soil deposit. The mean of maximum values of quasi-static, dynamic and total responses obtained from the two input models are compared with each other.

  10. Utilization of near-source video and ground motion in the assessment of seismic source functions from mining explosions

    SciTech Connect

    Stump, B.W.; Anderson, D.P.

    1995-04-01

    Constraint of the operative physical processes in the source region of mining explosions and the linkage to the generation of seismic waveforms provides the opportunity for controlling ground motion. Development of these physical models can also be used in conjunction with the ground motion data as diagnostics of blasting efficiency. In order to properly address the multi-dimensional aspect of data sets designed to constrain these sources, we are investigating a number of modem visualization tools that have only recently become available with new, high-speed graphical computers that can utilize relatively large data sets. The data sets that are combined in the study of mining explosion sources include near-source ground motion acceleration and velocity records, velocity of detonation measurements in each explosive hole, high speed film, video and shot design information.

  11. TriNet "ShakeMaps": Rapid generation of peak ground motion and intensity maps for earthquakes in southern California

    USGS Publications Warehouse

    Wald, D.J.; Quitoriano, V.; Heaton, T.H.; Kanamori, H.; Scrivner, C.W.; Worden, C.B.

    1999-01-01

    Rapid (3-5 minutes) generation of maps of instrumental ground-motion and shaking intensity is accomplished through advances in real-time seismographic data acquisition combined with newly developed relationships between recorded ground-motion parameters and expected shaking intensity values. Estimation of shaking over the entire regional extent of southern California is obtained by the spatial interpolation of the measured ground motions with geologically based frequency and amplitude-dependent site corrections. Production of the maps is automatic, triggered by any significant earthquake in southern California. Maps are now made available within several minutes of the earthquake for public and scientific consumption via the World Wide Web; they will be made available with dedicated communications for emergency response agencies and critical users.

  12. Ground motions associated with the design basis earthquake at the Savannah River Site, South Carolina, based on a deterministic approach

    SciTech Connect

    Youngs, R.R.; Coppersmith, K.J.; Stephenson, D.E.; Silva, W.

    1991-12-31

    Ground motion assessments are presented for evaluation of the seismic safety of K-Reactor at the Savannah River Site. Two earthquake sources are identified as the most significant to seismic hazard at the site, a M 7.5 earthquake occurring in Charleston, South Carolina, and a M 5 event occurring in the site vicinity. These events control the low frequency and high frequency portions of the spectrum, respectively. Three major issues were identified in the assessment of ground motions for the Savannah River site; specification of the appropriate stress drop for the Charleston source earthquake, specification of the appropriate levels of soil damping at large depths for site response analyses, and the appropriateness of western US recordings for specification of ground motions in the eastern US.

  13. Ground motions associated with the design basis earthquake at the Savannah River Site, South Carolina, based on a deterministic approach

    SciTech Connect

    Youngs, R.R.; Coppersmith, K.J. ); Stephenson, D.E. ); Silva, W. )

    1991-01-01

    Ground motion assessments are presented for evaluation of the seismic safety of K-Reactor at the Savannah River Site. Two earthquake sources are identified as the most significant to seismic hazard at the site, a M 7.5 earthquake occurring in Charleston, South Carolina, and a M 5 event occurring in the site vicinity. These events control the low frequency and high frequency portions of the spectrum, respectively. Three major issues were identified in the assessment of ground motions for the Savannah River site; specification of the appropriate stress drop for the Charleston source earthquake, specification of the appropriate levels of soil damping at large depths for site response analyses, and the appropriateness of western US recordings for specification of ground motions in the eastern US.

  14. Path durations for use in the stochastic‐method simulation of ground motions

    USGS Publications Warehouse

    Boore, David M.; Thompson, Eric M.

    2014-01-01

    The stochastic method of ground‐motion simulation assumes that the energy in a target spectrum is spread over a duration DT. DT is generally decomposed into the duration due to source effects (DS) and to path effects (DP). For the most commonly used source, seismological theory directly relates DS to the source corner frequency, accounting for the magnitude scaling of DT. In contrast, DP is related to propagation effects that are more difficult to represent by analytic equations based on the physics of the process. We are primarily motivated to revisit DT because the function currently employed by many implementations of the stochastic method for active tectonic regions underpredicts observed durations, leading to an overprediction of ground motions for a given target spectrum. Further, there is some inconsistency in the literature regarding which empirical duration corresponds to DT. Thus, we begin by clarifying the relationship between empirical durations and DT as used in the first author’s implementation of the stochastic method, and then we develop a new DP relationship. The new DP function gives significantly longer durations than in the previous DP function, but the relative contribution of DP to DT still diminishes with increasing magnitude. Thus, this correction is more important for small events or subfaults of larger events modeled with the stochastic finite‐fault method.

  15. A hybrid method of simulating broadband ground motion : A case study of the 2006 Pingtung earthquake, Taiwan

    NASA Astrophysics Data System (ADS)

    Yen, Y.; Ma, K.; Cheng, C.; Shao, K.; Lin, P.

    2011-12-01

    For the demand of engineering, the time-history of ground motions which consider the reliability and earthquake physical characters have been provided for earthquake resistant design of important building structures. However, the high frequency portion ( > 1 Hz) of near-fault ground motions was restricted by the insufficient resolution of velocity structure. Considering the relative small events which contain path and site effect in waveforms as Green's functions (i.e. empirical Green's function (EGF) method) can resolve the problem of lack of precise velocity structure to replace the path effect evaluation. Alternatively, a stochastic Green's function (SGF) method can be employed when the EGF is unavailable. Further, the low frequency ( < 1 Hz) can be obtained numerically by the Frequency-Wavenumber (FK) method. Thus, broadband frequency strong ground motion can be calculation by a hybrid method that combining a deterministic FK method for the low frequency simulation and the EGF or SGF method for high frequency simulation. The slip models had been investigated from Taiwan dense strong motion and global teleseismic data. Characterizing the slip models derived from the waveform inversion can directly extract the source parameters needed for the ground motion prediction in the EGF method or the SGF method. The nuclear power plant in southern tip of Taiwan was experienced a strong shaking by the 26 December 2006 Pingtung, Taiwan offshore earthquake. The closest strong motion station of the Central Weather Bureau, KAU082, recorded the peak acceleration value (PGA) of 0.24 g. We considered the adjacent stations to be the case study for possibility evaluation of predicting ground motion utilizing the EGF method or SGF method. The possible damage impact toward nuclear power plant for specific sites can be estimated and verified according to the simulation results

  16. Long-Period Ground Motion in the Arabian Gulf from Earthquakes in the Zagros Mountains Thrust Belt

    NASA Astrophysics Data System (ADS)

    Pitarka, Arben; Al-Amri, Abdullah; Pasyanos, Michael E.; Rodgers, Arthur J.; Mellors, Robert J.

    2015-10-01

    The Arabian Gulf is adjacent to the Zagros Mountains, one of the most seismically active regions in the world. We observe that broadband seismic records of Zagros earthquakes recorded on the Arabian side of the Gulf display long-duration surface waves. While shorter periods (<1 s) are attenuated from crossing the deep sediments (>10 km) of the Gulf basin, the long-period energy is enhanced and transmitted efficiently. Consequently, large earthquakes in the Zagros could result in amplified ground motions at long periods (2-10 s) relative to average behavior. Such ground motions are of concern for large engineered structures, such as tall buildings and long bridges with resonant periods in the same period range. Here we present results of investigations of the characteristics of ground motions recorded on the western shore of the Gulf from selected earthquakes in the Zagros Mountains region. Exceptionally, long-duration seismic waves, as compared with standard models, are shown to occur with periods of 2-10 s. This may be due to waveguide effects in the deep sedimentary basin structure of the Arabian Platform. In addition to analyzing recorded ground motion we performed 3D wave propagation simulations using a finite difference method and experimental velocity models of the Gulf, with different shallow sedimentary layers structures. The simulation results confirm our hypothesis that long-period waves with extremely long duration and relatively large amplitudes are caused by the geometry of the basin sedimentary layers and, to some extent, by shallow earthquake depths. Combined effects of basin edge geometry with sharp velocity contrasts and shallow sources (<10 km) on the eastern side of the Arabian Gulf can cause large long-period ground motion on the western side of the Gulf. In contrast, the short-period content of ground motion (<2 s) at long distances is relatively weak. This is mainly due to wave propagation scattering and attenuation in the shallow sedimentary

  17. Physically-Based Ground Motion Prediction and Validation A Case Study: Mid-sized Marmara Sea Earthquakes

    NASA Astrophysics Data System (ADS)

    Mert, A.

    2015-12-01

    In this study we have two main purposes. The first one is to simulate five midsize earthquakes (Mw≈5.0) recorded in the Marmara region, which has a geologically complex and heterogeneous crustal structure. We synthesize ground motion for the full wave train on three components, and applied a 'physics based' solution of earthquake rupture. The simulation methodology is based on the studies by Hutchings et al. (2007), Scognamiglio and Hutchings (2009). For each earthquake, we synthesized seismograms using by 500 different rupture scenarios that were generated by Monte Carlo selection of parameters within the range. Synthetic ground motion is a major challenge for seismic hazard assessment studies. Especially after the adoption of performance-based design approach with the Earthquake resistant design of engineering structures. To compute realistic time histories for different locations around Marmara region can be helpful for engineering design, retrofitting the existing structures, hazard and risk management studies and developing new seismic codes and standards.The second purpose is to validate synthetic seismograms with real seismograms. We follow the methodology presented by Anderson (2003) for validation. This methodology proposes a similarity score based on averages of the quality of fit measuring ground motion characteristics and uses a suite of measurements. Namely, the synthetics are compared to real data by ten representative ground motion criteria. The applicability of Empirical Green's functions methodology and physics based solution of earthquake rupture had been assessed in terms of modeling in complex geologic structure. Because the methodology produces source and site specific synthetic ground motion time histories and goodness-of-fit scores of obtained synthetics is between 'fair' to 'good' range based on Anderson's score, we concluded that it can be tried to produce ground motion that has not previously been recorded during catastrophic earthquake

  18. Sensitivity of Base-Isolated Systems to Ground Motion Characteristics: A Stochastic Approach

    SciTech Connect

    Kaya, Yavuz; Safak, Erdal

    2008-07-08

    Base isolators dissipate energy through their nonlinear behavior when subjected to earthquake-induced loads. A widely used base isolation system for structures involves installing lead-rubber bearings (LRB) at the foundation level. The force-deformation behavior of LRB isolators can be modeled by a bilinear hysteretic model. This paper investigates the effects of ground motion characteristics on the response of bilinear hysteretic oscillators by using a stochastic approach. Ground shaking is characterized by its power spectral density function (PSDF), which includes corner frequency, seismic moment, moment magnitude, and site effects as its parameters. The PSDF of the oscillator response is calculated by using the equivalent-linearization techniques of random vibration theory for hysteretic nonlinear systems. Knowing the PSDF of the response, we can calculate the mean square and the expected maximum response spectra for a range of natural periods and ductility values. The results show that moment magnitude is a critical factor determining the response. Site effects do not seem to have a significant influence.

  19. The historical seismicity and prediction of ground motion in northeast Mexico

    NASA Astrophysics Data System (ADS)

    Galván-Ramírez, Iván N.; Montalvo-Arrieta, Juan C.

    2008-02-01

    This work constitutes the first attempt to understand the seismic hazard in northeast Mexico. We present a compilation of regional seismicity in northeast Mexico (24-31°N, 97-106°W), finding 148 earthquakes for the 1787-2006 period. The study area lies within three morphotectonic provinces: Basin, Range, and Rio Grande rift; Sierra Madre Oriental; and Gulf coastal plain. Peak ground acceleration (PGA) maps were computed for three different scenarios: 1928 Parral, Chihuahua ( MW = 6.5); 1931 Valentine, Texas ( MW = 6.4); and a hypothetical earthquake located in central Coahuila. Ground motion values were computed using attenuation relations developed for central and eastern North America and the Basin and Range provinces. The earthquake in central Coahuila is considered a critical scenario for the main cities of northeast Mexico. The damage associated with this hypothetical earthquake could be severe because most buildings were constructed without seismic criteria. The expected PGA values in Monterrey, Saltillo, and Monclova are between 30 and 70 cm/s 2. This earthquake might also produce or trigger significant landslides and rock falls in the Sierra Madre Oriental, where several cities are located on the mountain range.

  20. Preliminary results of strong ground motion simulation for the Lushan earthquake of 20 April 2013, China

    NASA Astrophysics Data System (ADS)

    Zhu, Gengshang; Zhang, Zhenguo; Wen, Jian; Zhang, Wei; Chen, Xiaofei

    2013-08-01

    The earthquake occurred in Lushan County on 20 April, 2013 caused heavy casualty and economic loss. In order to understand how the seismic energy propagates during this earthquake and how it causes the seismic hazard, we simulated the strong ground motions from a representative kinematic source model by Zhang et al. (Chin J Geophys 56(4):1408-1411, 2013) for this earthquake. To include the topographic effects, we used the curved grids finite difference method by Zhang and Chen (Geophys J Int 167(1):337-353, 2006), Zhang et al. (Geophys J Int 190(1):358-378, 2012) to implement the simulations. Our results indicated that the majority of seismic energy concentrated in the epicentral area and the vicinal Sichuan Basin, causing the XI and VII degree intensity. Due to the strong topographic effects of the mountain, the seismic intensity in the border area across the northeastern of Boxing County to the Lushan County also reached IX degree. Moreover, the strong influence of topography caused the amplifications of ground shaking at the mountain ridge, which is easy to cause landslides. These results are quite similar to those observed in the Wenchuan earthquake of 2008 occurred also in a strong topographic mountain area.

  1. Probabilistic sensitivity analysis of two suspension bridges in Istanbul, Turkey to near- and far-fault ground motion

    NASA Astrophysics Data System (ADS)

    Çavdar, Ö.

    2012-02-01

    The aim of this paper is to compare the near-fault and far-fault ground motion effects on the probabilistic sensitivity dynamic responses of two suspension bridges in Istanbul. Two different types of suspension bridges are selected to investigate the near-fault (NF) and far-fault (FF) ground motion effects on the bridge sensitivity responses. NF and FF strong ground motion records, which have approximately identical peak ground accelerations, of the Kocaeli (1999) earthquake are selected for the analyses. Displacements and internal forces are determined using the probabilistic sensitivity method (PSM), which is one type of stochastic finite element method. The efficiency and accuracy of the proposed algorithm are validated by comparison with results of the Monte Carlo Simulation (MCS) method. The displacements and internal forces obtained from the analyses of suspension bridges subjected to each fault effect are compared with each other. It is clearly seen that there is more seismic demand on displacements and internal forces when suspension bridges are subjected to NF and FF ground motion.

  2. Ground Motions at a Network of Strong Motion Accelerometers on the Hanford Site, Southeastern Washington, From the 28 February 2001 Nisqually Earthquake

    NASA Astrophysics Data System (ADS)

    Rohay, A.; Reidel, S.; Hartshorn, D.; Valenta, M.

    2001-12-01

    We have been operating five free-field strong motion accelerometers (SMA) at locations near the facilities on the Hanford Site since November 1998. The 28 February 2001 Nisqually earthquake was the first earthquake to be recorded by these instruments. The USGS and Caltech each operate one additional SMA/broadband seismometer site at Hanford (stations HAWA and LTH). Taken together, the elements of this network have an inter-station spacing of 8-12 km. The distance range of the instruments from the epicenter is 245-277 km. Peak ground accelerations ranged from 0.0016 to 0.0035 g (vertical), from 0.0017 to 0.0057 g (radial), and from 0.0022 to 0.0064 g (transverse). The lowest accelerations were observed at the bedrock site HAWA, but accelerations at another station on soil (H300A) were not significantly larger. The other stations on soil show significant amplification across the frequency spectrum and also within variable, narrow frequency ranges. For example, Fourier spectra from the station H100K, the furthest north of these stations, shows nearly a factor of 10 amplification of the transverse ground acceleration in the frequency range 0.5 to 1.0 Hz relative to the bedrock station. We are investigating the differences in soil geology beneath the network of SMA stations to understand these effects. The ground motions recorded from this earthquake are significantly lower than those predicted by intra-slab earthquake ground motion attenuation relationships that were used for Hanford's probabilistic seismic hazard assessment. Although these relationships include statistical variation in ground motion, they do not predict the range of amplification determined at the soil sites for this earthquake. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy under contract DE-AC06-76RL01830.

  3. Investigations in site response from ground motion observations in vertical arrays

    NASA Astrophysics Data System (ADS)

    Baise, Laurie Gaskins

    The aim of the research is to improve the understanding of earthquake site response and to improve the techniques available to investigate issues in this field. Vertical array ground motion data paired with the empirical transfer function (ETF) methodology is shown to accurately characterize site response. This manuscript draws on methods developed in the field of signal processing and statistical time series analysis to parameterize the ETF as an autoregressive moving-average (ARMA) system which is justified theoretically, historically, and by example. Site response is evaluated at six sites in California, Japan, and Taiwan using ETF estimates, correlation analysis, and full waveform modeling. Correlation analysis is proposed as a required data quality evaluation imperative to any subsequent site response analysis. ETF estimates and waveform modeling are used to decipher the site response at sites with simple and complex geologic structure, which provide simple time-invariant and time-variant methods for evaluating both linear site transfer functions and nonlinear site response for sites experiencing liquefaction of the soils. The Treasure and Yerba Buena Island sites, however, require 2-D waveform modeling to accurately evaluate the effects of the shallow sedimentary basin. ETFs are used to characterize the Port Island site and corresponding shake table tests before, during, and after liquefaction. ETFs derived from the shake table tests were demonstrated to consistently predict the linear field ground response below 16 m depth and the liquefied behavior above 15 m depth. The liquefied interval response was demonstrated to gradually return to pre-liquefied conditions within several weeks of the 1995 Hyogo-ken Nanbu earthquake. Both the site's and the shake table test's response were shown to be effectively linear up to 0.5 g in the native materials below 16 m depth. The effective linearity of the site response at GVDA, Chiba, and Lotting up to 0.1 g, 0.33 g, and

  4. Prediction of ground motion parameters for the volcanic area of Mount Etna

    NASA Astrophysics Data System (ADS)

    Tusa, Giuseppina; Langer, Horst

    2016-01-01

    Ground motion prediction equations (GMPEs) have been derived for peak ground acceleration (PGA), velocity (PGV), and 5 % damped spectral acceleration (PSA) at frequencies between 0.1 and 10 Hz for the volcanic area of Mt. Etna. The dataset consists of 91 earthquakes with epicentral distances between 0.5 and 100 km. Given the specific characteristics of the area, we divided our data set into two groups: shallow events (SE, focal depth <5 km), and deep events (DE, focal depth >5 km). The range of magnitude covered by the SE and the DE is 3.0 ≤ M L ≤ 4.3 and 3.0 ≤ M L ≤ 4.8, respectively. Signals of DE typically have more high frequencies than those of SE. These differences are clearly reflected in the empirical GMPEs of the two event groups. Empirical GMPEs were estimated considering several functional forms: Sabetta and Pugliese (Bull Seism Soc Am 77:1491-1513, 1987) (SP87), Ambraseys et al. (Earth Eng Struct Dyn 25:371-400, 1996) (AMB96), and Boore and Atkinson (Earth Spectra 24:99-138, 2008) (BA2008). From ANOVA, we learn that most of the errors in our GMPEs can be attributed to unmodeled site effects, whereas errors related to event parameters are limited. For DE, BA2008 outperforms the simpler models SP87 or AMB96. For SE, the simple SP87 is preferable considering the Bayesian Information Criterion since it proves more stable with respect to confidence and gives very similar or even lower prediction errors during cross-validation than the BA2008 model. We compared our results to relationships derived for Italy (ITA10, Bindi et al. Bull Earth Eng 99:2471-2488, 2011). For SE, the main differences are observed for distances greater than about 5 km for both horizontal and vertical PGAs. Conversely, for DE the ITA10 heavily overestimates the peak ground parameters for short distances.

  5. Updated Graizer-Kalkan Ground Motion Prediction Equations for Western United States

    NASA Astrophysics Data System (ADS)

    Graizer, V.

    2013-12-01

    Ground motion prediction equations (GMPEs) for peak-ground acceleration (PGA) and 5-percent damped pseudo spectral accelerations (SA) of horizontal component ground motions were developed by Graizer and Kalkan (2007, 2009) using the extended ground motion database of the Next Generation of Attenuation project for shallow crustal earthquakes in active tectonic regions. The main features of these GMPEs (GK09) are: (1) only most essential measureable parameters [moment magnitude (M), closest distance to the fault rupture, style of faulting and average shear-wave velocity in the upper 30 meters of profile under the site (Vs30)] are used; (2) predictive model for SA is a continuous function of spectral period (T), which eliminates the standard matrix of estimator coefficients, and allows for calculation of SA at any period of interest within the model range of 0.01 to 10 sec; (3) mathematical form of GMPEs constitutes a series of filters--each filter represents a certain physical phenomenon affecting the radiation of seismic waves from the source. In contrast to the existing GMPEs, GK09 predictive model allows PGA to reach its maximum value at some distance from the fault effectively capturing the phenomenon observed in earthquakes with large number of near-source recordings such as the 1979 (M6.5) Imperial Valley and the 2004 (M6.0) Parkfield earthquakes. The GK09 GMPEs are shown to provide accuracy (expected median prediction without significant bias) and efficiency (relatively small standard error of predictions) as compared to recorded data at distances of up to 250 km during recent shallow-crustal earthquakes with 5.0≤M≤7.9 including the 2008 (M7.9) Wenchuan (China), 2010 (M7.2) El-Mayor Cucapah (Mexico), 2011 (M6.3) Christchurch (New Zealand) and other earthquakes. The GK09 GMPEs are updated here by adding an anelastic attenuation filter as a function of quality-factor (Q), and by improving the existing basin-effect filter, which is now a function of depth

  6. Information Sharing Between Ground Motion Models from Different Regions via Dirichlet Process Priors

    NASA Astrophysics Data System (ADS)

    Hermkes, M.; Kuehn, N.; Riggelsen, C.; Vogel, K.

    2012-04-01

    In probabilistic seismic hazard analysis (PSHA) seismic ground motion data, induced by earthquakes, are collected at different geographical regions. Instead of building ground motion models, which estimates intensity parameters, e.g. peak ground acceleration or spectral acceleration, given earthquake and site related parameters, for each region individually, it is preferable to share information across the regions to increase the overall prediction performance. One of the most important methods to share information correlation between models is Hierarchical Bayesian modeling, where parameters of the region-specific models are coupled by a common prior. As a result of learning the parameters of the model and the hyperparameters of the common prior jointly, the function estimation of a specific region is affected by its own training data and by data from the other region related through the coupled prior. Generally, the common prior is specified in a parametric form with unknown hyperparameters. A drawback of such a prior by reason of its modality is that the relationship between all ground motion models are treated equally, but it is desirable that only similar models share information to permit negative transfer. To deal with these issues we propose a nonparametric hierarchical Bayesian model where the common prior is drawn from a Dirichlet Process (DP). Such a nonparametric prior has the ability to fit the model well with respect to the data without restriction about the functional form of the prior distribution. Furthermore, the employed DP prior induces a partition of region-specific models, so that models within each cluster share the same parameterization. First of all, we present a linear regression model, for which the weights of the covariates and the model variance are drawn from a DP prior. As base distribution for the DP we have chosen a normal inverse-Gamma prior which is the natural conjugate prior to the normal likelihood of the applied regression

  7. An Effective and Fairly Simple Expression for Predicting the Polarization of Strong Ground Motions

    NASA Astrophysics Data System (ADS)

    Spudich, P.; Chiou, B.

    2006-12-01

    Fault-normal ground motions often exceed fault-parallel motions within a few km of the surface trace of faults that rupture in large (M>6.0) earthquakes (Somerville et al., Seismol. Res. Let., 1997). We seek a very simple method for predicting the S-wave polarization of a hypothetical earthquake. Our method uses the S-wave radiation pattern of two point double-couples to predict the ratio of fault-normal to fault-parallel motion in the region around a finite fault having a uniform slip distribution and known rake. One point source is located at the hypocenter, and the other is located at a theoretically optimal intermediate point lying on the line between the hypocenter and the point on the fault closest to the observation location. For both radiation patterns we assume that the S wave travels a straight line from its point source to the observation location, and that the S wave is vertically incident at the Earth's surface, to account for ray bending from low velocity near-surface materials. We also assume that nodes in the radiation patterns are filled with an empirically determined water- level that depends on frequency and distance to the observation point. We have determined the empirical water-level by comparison of our predictions with observed fault-normal and fault-parallel response spectral accelerations in the 0.5 - 6.0 s band from 39 earthquake having M = 6.0 or greater, taken from the data set of the Next Generation Attenuation Project of the PEER Lifelines Project. At 0.4 s almost no evidence of systematic polarization can be seen in the data. However, as period increases stronger polarization can be seen in the data at progressively larger distances from the source, extending as far as 200 km. Our predictions of fault-normal / fault-parallel motion fit the data better than those of Somerville et al. (1997) for all distances greater than 5 km, but our predictions are worse than Somerville's for sites within 2 km of a rupturing fault.

  8. On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs)

    NASA Astrophysics Data System (ADS)

    Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter

    2016-04-01

    Often, scaling of response spectral amplitudes, (e.g., spectral acceleration) obtained from empirical ground motion prediction equations (GMPEs), with respect to commonly used seismological parameters such as magnitude, distance and site condition is assumed/referred to be representing a similar scaling of Fourier spectral amplitudes. For instance, the distance scaling of response spectral amplitudes is related with the geometrical spreading of seismic waves. Such comparison of scaling of response spectral amplitudes with that of corresponding Fourier spectral amplitudes is motivated by that, the functional forms of response spectral GMPEs are often derived using the concepts borrowed from Fourier spectral modeling of ground motion. As these GMPEs are subsequently calibrated with empirical observations, this may not appear to pose any major problems in the prediction of ground motion for a particular earthquake scenario. However, the assumption that the Fourier spectral concepts persist for response spectra can lead to undesirable consequences when it comes to the adjustment of response spectral GMPEs to represent conditions not covered in the original empirical data set. In this context, a couple of important questions arise, e.g., what are the distinctions and/or similarities between Fourier and response spectra of ground-motions? And, if they are different, then what is the mechanism responsible for such differences and how do adjustments that are made to FAS manifest in response spectra? We explore the relationship between the Fourier and response spectrum of ground motion by using random vibration theory (RVT). With a simple Brune (1970, 1971) source model, RVT-generated acceleration spectra for a fixed magnitude and distance scenario are used. The RVT analyses reveal that the scaling of low oscillator-frequency response spectral ordinates can be treated as being equivalent to the scaling of the corresponding Fourier spectral ordinates. However, the high

  9. Physics-Based Long-Period Ground Motion Scenarios in and Around the Po Plain Sedimentary Basin (Northern Italy)

    NASA Astrophysics Data System (ADS)

    Molinari, I.; Morelli, A.; Casarotti, E.

    2014-12-01

    Unexpected large and prolonged shaking (> 80s) associated with long-period ground motion has been observed inside the Po Plain sedimentary basin (Northern Italy) during the two M~6, May 20-29, 2012, earthquakes. Long-period ground motion impacts on the seismic response of taller structures. It is hence important to understand the characteristics of long-period ground motion associated with the 3D structure and finite fault properties, in particular in those regions with deep sedimentary basins and a complex geological context. We implement a recent high resolution model of the Po basin (MAMBo), derived from geological constraints, in spectral-element code SPECFEM3D_cartesian (Peter et al., 2012). The simulations are numerically accurate for periods of 2 sec and longer, and incorporate complex 3D basin structure and topography as well as the spatial and temporal heterogeneity of source rupture. The response of our basin model has been evaluated for several instrumental earthquakes. Synthetics seismograms reproduce well amplitude and long duration, as well as envelope and coda, observed in paths that travel through sediments. We also evaluate ground motion produced by plausible earthquakes inferred from historical data, such as the Modena (1501) and Verona (1117) events that caused well-documented strong effects in a unusually wide areas with lengths of hundreds of kilometers. We test different representations of the seismic source, from point source to finite sources with different rupture histories, evaluating the impact on shaking amplitude. We compare our results with damage maps (when available) and with the GMPEs currently adopted for this area, evaluating the effects of finite fault and 3D propagation on ground shaking. We show that deterministic ground motion calculation can indeed provide information to be actively used to mitigate the effects of destructive earthquakes on critical infrastructures.

  10. Validation of a ground motion synthesis and prediction methodology for the 1988, M=6.0, Saguenay Earthquake

    SciTech Connect

    Hutchings, L.; Jarpe, S.; Kasameyer, P.; Foxall, W.

    1998-01-01

    We model the 1988, M=6.0, Saguenay earthquake. We utilize an approach that has been developed to predict strong ground motion. this approach involves developing a set of rupture scenarios based upon bounds on rupture parameters. rupture parameters include rupture geometry, hypocenter, rupture roughness, rupture velocity, healing velocity (rise times), slip distribution, asperity size and location, and slip vector. Scenario here refers to specific values of these parameters for an hypothesized earthquake. Synthetic strong ground motion are then generated for each rupture scenario. A sufficient number of scenarios are run to span the variability in strong ground motion due to the source uncertainties. By having a suite of rupture scenarios of hazardous earthquakes for a fixed magnitude and identifying the hazard to the site from the one standard deviation value of engineering parameters we have introduced a probabilistic component to the deterministic hazard calculation, For this study we developed bounds on rupture scenarios from previous research on this earthquake. The time history closest to the observed ground motion was selected as a model for the Saguenay earthquake.

  11. Design of a low-cost servo-actuated shaking table for simulating ground motions with strong vertical component

    NASA Astrophysics Data System (ADS)

    Tsolakis, Efstratios

    2014-10-01

    This article proposes a new set of configurationsfor the construction of a low cost servo-actuatedshake table with a wide range simulation ability, especially regarding ground motions with strong vertical components up to 3.86g and 1.62m acceleration and stroke respectively. Designing decision and challenges faced during the process are also presented.

  12. Cost-effective monitoring of ground motion by joint use of a single-frequency GPS and a MEMS accelerometer

    NASA Astrophysics Data System (ADS)

    Tu, Rui; Wang, Rongjiang; Ge, Maorong; Walter, Thomas R.; Ramatschi, Markus; Milkereit, Claus; Bindi, Dino; Dahm, Torsten

    2014-05-01

    Real-time detection and precise estimation of strong ground motion are crucial for rapid assessment and early warning of geohazards such as earthquakes, landslides, and volcanic activity. This challenging task can be accomplished by combining GPS and accelerometer measurements because of their complementary capabilities to resolve broadband ground motion signals. However, for implementing an operational monitoring network of such joint measurement systems, cost-effective techniques need to be developed and rigorously tested. We propose a new approach for joint processing of single-frequency GPS and MEMS (micro-electro-mechanical systems) accelerometer data in real time. To demonstrate the performance of our method, we describe results from outdoor experiments under controlled conditions. For validation, we analysed dual-frequency GPS data and images recorded by a video camera. The results of the different sensors agree very well, suggesting that real-time broadband information of ground motion can be provided by using single-frequency GPS and MEMS accelerometers. Reference: Tu, R., R. Wang, M. Ge, T. R. Walter, M. Ramatschi, C. Milkereit, D. Bindi, and T. Dahm (2013), Cost-effective monitoring of ground motion related to earthquakes, landslides, or volcanic activity by joint use of a single-frequency GPS and a MEMS accelerometer, Geophysical Research Letters, 40, 3825-3829, doi:10.1002/grl.50653.

  13. Effect of directionality of multi-component ground motions on bridge fragility curves

    NASA Astrophysics Data System (ADS)

    Torbol, Marco

    This dissertation focuses on developing, evaluating and testing a new approach to seismic risk assessment of highway transportation networks. Throughout the years many researches have been conducted on each different step used in this dissertation. Most of these steps use a probabilistic approach for each single problem; Monte Carlo simulation is the brute force approach used by this dissertation, however some assumptions throughout the process were necessary to achieve results that could be useful to the final user, decision maker. When dealing with the damageability of an infrastructure network, it is necessary to start from the study of the damageability of each vulnerable component. For highway transportation networks subject to a seismic event bridges are the vulnerable component. With enough time, enough information and enough manpower the best approach is step by step: to build an analytical model for each bridge, to perform probabilistic seismic hazard analysis PSHA at each bridge site and to assess the seismic vulnerability of each bridge. Unfortunately, when dealing with large networks, bridges are present in hundreds or even thousands (LA-OC network has more than 3000 bridges; therefore subdivision in classes and prototyping of each class is necessary to reduce the problem to a more manageable dimension. a single prototype that represents its entire class is analyzed and its damageability is applied to the entire class. Fragility curves will be used to represents the bridges' damageability. Different contributions are developed in this dissertation; the fundamental one is the development of fragility curves with two uni-variate random variables. The first will be the Intensity Measure of the ground motion; the second will be the angle of seismic incidence from which the ground motion struck the structure. Bridges with the same damageability class, located at different places within the network will behave differently under the same earthquake scenario

  14. Site-specific strong ground motion prediction using 2.5-D modelling

    NASA Astrophysics Data System (ADS)

    Narayan, J. P.

    2001-08-01

    An algorithm was developed using the 2.5-D elastodynamic wave equation, based on the displacement-stress relation. One of the most significant advantages of the 2.5-D simulation is that the 3-D radiation pattern can be generated using double-couple point shear-dislocation sources in the 2-D numerical grid. A parsimonious staggered grid scheme was adopted instead of the standard staggered grid scheme, since this is the only scheme suitable for computing the dislocation. This new 2.5-D numerical modelling avoids the extensive computational cost of 3-D modelling. The significance of this exercise is that it makes it possible to simulate the strong ground motion (SGM), taking into account the energy released, 3-D radiation pattern, path effects and local site conditions at any location around the epicentre. The slowness vector (py) was used in the supersonic region for each layer, so that all the components of the inertia coefficient are positive. The double-couple point shear-dislocation source was implemented in the numerical grid using the moment tensor components as the body-force couples. The moment per unit volume was used in both the 3-D and 2.5-D modelling. A good agreement in the 3-D and 2.5-D responses for different grid sizes was obtained when the moment per unit volume was further reduced by a factor equal to the finite-difference grid size in the case of the 2.5-D modelling. The components of the radiation pattern were computed in the xz-plane using 3-D and 2.5-D algorithms for various focal mechanisms, and the results were in good agreement. A comparative study of the amplitude behaviour of the 3-D and 2.5-D wavefronts in a layered medium reveals the spatial and temporal damped nature of the 2.5-D elastodynamic wave equation. 3-D and 2.5-D simulated responses at a site using a different strike direction reveal that strong ground motion (SGM) can be predicted just by rotating the strike of the fault counter-clockwise by the same amount as the azimuth of

  15. Combination of Insar and GPS to Measure Ground Motions and Atmospheric Signals

    NASA Astrophysics Data System (ADS)

    Zerbini, S.; Prati, C.; Errico, M.; Ferri, S.; Novali, F.; Scirpoli, S.; Tiberi, L.

    2010-12-01

    The combination of different techniques such as InSAR and GPS is characterized by the added value of taking advantage of their complementary strengths and of minimizing their respective weaknesses, thus allowing for the full exploitation of the complementary aspects by overcoming the limitations inherent in the use of each technique alone. Another important aspect of the GPS/InSAR integration regards the fact that today’s application of interferometric SAR techniques is limited by the knowledge of the wet tropospheric path delay in microwave observations. GPS-based estimates of tropospheric delays may help in obtaining better corrections which will enhance the coherence and will allow the application of InSAR in a wider range of applications. The area selected for the InSAR/GPS comparison/integration is in northeastern Italy and includes the town of Bologna, and two nearby sites Medicina (agricultural area) and Loiano (a small city on the Apennines) where a small network of permanent GPS stations is operated by the University of Bologna. The InSAR data used are the COSMO-SkyMed (CSK) images made available by the Italian Space Agency (ASI) in the framework of the research contract AO-1140. The Permanent Scatterers (PS) technique will be applied to a number of repeated CSK strip map SAR images acquired over a 40x40 square km area encompassing the towns mentioned above. Ultimately this work will contribute demonstrating the CSK capabilities to operate in a repeated interferometric survey mode for measuring ground deformation with millimeter accuracy in different environments. A PS is a target whose radar signature is stable with time. Such targets can be identified by means of multiple SAR observations and they can be exploited for jointly estimating their relative motion and the atmospheric artifacts on a grid that can be quite dense in space but not in time (depending on the SAR revisiting time interval). On the contrary the GPS can provide very frequent time

  16. Integration of Near-fault Earthquake Ground Motion Simulations in Damage and Loss Estimation Procedures.

    NASA Astrophysics Data System (ADS)

    Faccioli, E.; Lagomarsino, S.; Demartinos, K.; Smerzini, C.; Stuppazzini, M.; Vanini, M.; Villani, M.; Smolka, A.; Allmann, A.

    2010-05-01

    In this contribution we investigate the advantages and/or limitations of integrating standard approaches for damage and loss estimation procedures with synthetic data from 3D large scale numerical simulations, capable to reproduce the coupling of near-fault conditions, including the focal mechanism of the source and directivity effects, and complex geological configurations, such as deep alluvial basins or irregular topographic profiles. As a matter of fact, the largest portion of damage and losses during a major earthquake occur in near-field conditions, where earthquake ground motion is typically poorly constrained based on standard attenuation relationships, that may not be based on a sufficiently detailed description both of the seismic source and of the local geological conditions. As a case study we decided to use a scenario earthquake of Mw 6.4 occurring in the town of Sulmona, Italy along the active Mount Morrone fault. The area, located only 40 km south of l'Aquila, was selected in the frame of the Italian Project S2 (DPC-INGV 2007-2009) thanks to the amount of geological and seismological information that allowed on one hand to perform near-fault 3D earthquake ground motion simulations, and, on the other side, a reliable quantification of the potential damage thanks to the accurate data characterizing the building stocks. The 3D simulations have been carried out through a high performance Spectral Elements tool, namely GeoELSE (http://geoelse.stru.polimi.it), designed to study linear, non-linear viscoelastic and viscoplastic wave propagation analyses in large-scale earth models, including the seismic source, the propagation path, the local near-surface geology, and, if needed, the interaction with man-made structures . The parallel implementation of the code GeoELSE ensures a reasonable computer time to resolve tens of million of degrees of freedom up to 2.5 Hz. Damage and loss evaluations based on the results of numerical simulations are compared with

  17. SMSIM--Fortran programs for simulating ground motions from earthquakes: Version 2.0.--a revision of OFR 96-80-A

    USGS Publications Warehouse

    Boore, David M.

    2000-01-01

    A simple and powerful method for simulating ground motions is based on the assumption that the amplitude of ground motion at a site can be specified in a deterministic way, with a random phase spectrum modified such that the motion is distributed over a duration related to the earthquake magnitude and to distance from the source. This method of simulating ground motions often goes by the name "the stochastic method." It is particularly useful for simulating the higher-frequency ground motions of most interest to engineers, and it is widely used to predict ground motions for regions of the world in which recordings of motion from damaging earthquakes are not available. This simple method has been successful in matching a variety of ground-motion measures for earthquakes with seismic moments spanning more than 12 orders of magnitude. One of the essential characteristics of the method is that it distills what is known about the various factors affecting ground motions (source, path, and site) into simple functional forms that can be used to predict ground motions. SMSIM is a set of programs for simulating ground motions based on the stochastic method. This Open-File Report is a revision of an earlier report (Boore, 1996) describing a set of programs for simulating ground motions from earthquakes. The programs are based on modifications I have made to the stochastic method first introduced by Hanks and McGuire (1981). The report contains source codes, written in Fortran, and executables that can be used on a PC. Programs are included both for time-domain and for random vibration simulations. In addition, programs are included to produce Fourier amplitude spectra for the models used in the simulations and to convert shear velocity vs. depth into frequency-dependent amplification. The revision to the previous report is needed because the input and output files have changed significantly, and a number of new programs have been included in the set.

  18. Macroseismic Intensity and Instrumental Ground Motion Parameter Correlations for Central Mexico

    NASA Astrophysics Data System (ADS)

    Sandoval Gómez, H.; Ramirez Guzman, L.; Espindola, V.

    2012-12-01

    We present instrumental intensity prediction equations for earthquakes in Central Mexico based on the correlation of observed Instrumental Ground-Motion Parameters (IGMP) and Modified Mercalli Intensity (MMI) scale reports. The goal of this study is to provide a model that can be used by the near real-time earthquake response system operated by the Institutes of Engineering and Geophysics at the National Autonomous University of Mexico (UNAM), which delivers estimates of key information associated with the societal impact due to earthquakes not available in the immediate aftermath of the event. Correlations of MMI and IGMP have been derived in other countries with different tectonic settings and built environments, but this is the first study devoted to the development of equations for the central region of Mexico. The IGMP are obtained from records of several stations for earthquakes with Mw 5.0-8.0 from the seismic networks operated by UNAM and other institutions in Mexico. The MMI observations were primarily obtained from the Did You Feel It (DYFI) report service of the U.S. Geological Survey and re-interpreted MMI reports from UNAM earthquake bulletin archives. For each instrumental observation we assigned a mean MMI intensity based on the proximity of the site where reported value are available, constrained by geological conditions and a visual inspection to guarantee that the intensity would be within one unit of the assigned value; following the procedure by Atkinson and Kaka (2006). We derived correlations for peak ground velocity (pgv) and acceleration, and three spectral acceleration periods (T=1, 2 and 3 s). In addition, we analyzed the Mw and distance dependence. We concluded that pgv and the spectral accelerations are the most useful IGMP predictors for MMI in the region of interest and the correlations differ significantly from those obtained in regions with other tectonic settings and infrastructure vulnerabilities (e.g. Wald et al, 1999; Atkinson

  19. Fault geometry, rupture dynamics and ground motion from potential earthquakes on the North Anatolian Fault under the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Oglesby, David D.; Mai, P. Martin

    2012-03-01

    Using the 3-D finite-element method, we develop dynamic spontaneous rupture models of earthquakes on the North Anatolian Fault system in the Sea of Marmara, Turkey, considering the geometrical complexity of the fault system in this region. We find that the earthquake size, rupture propagation pattern and ground motion all strongly depend on the interplay between the initial (static) regional pre-stress field and the dynamic stress field radiated by the propagating rupture. By testing several nucleation locations, we observe that those far from an oblique normal fault stepover segment (near Istanbul) lead to large through-going rupture on the entire fault system, whereas nucleation locations closer to the stepover segment tend to produce ruptures that die out in the stepover. However, this pattern can change drastically with only a 10° rotation of the regional stress field. Our simulations also reveal that while dynamic unclamping near fault bends can produce a new mode of supershear rupture propagation, this unclamping has a much smaller effect on the speed of the peak in slip velocity along the fault. Finally, we find that the complex fault geometry leads to a very complex and asymmetric pattern of near-fault ground motion, including greatly amplified ground motion on the insides of fault bends. The ground-motion pattern can change significantly with different hypocentres, even beyond the typical effects of directivity. The results of this study may have implications for seismic hazard in this region, for the dynamics and ground motion of geometrically complex faults, and for the interpretation of kinematic inverse rupture models.

  20. How sensitive is earthquake ground motion to source parameters? Insights from a numerical study in the Mygdonian basin

    NASA Astrophysics Data System (ADS)

    Chaljub, Emmanuel; Maufroy, Emeline; deMartin, Florent; Hollender, Fabrice; Guyonnet-Benaize, Cédric; Manakou, Maria; Savvaidis, Alexandros; Kiratzi, Anastasia; Roumelioti, Zaferia; Theodoulidis, Nikos

    2014-05-01

    Understanding the origin of the variability of earthquake ground motion is critical for seismic hazard assessment. Here we present the results of a numerical analysis of the sensitivity of earthquake ground motion to seismic source parameters, focusing on the Mygdonian basin near Thessaloniki (Greece). We use an extended model of the basin (65 km [EW] x 50 km [NS]) which has been elaborated during the Euroseistest Verification and Validation Project. The numerical simulations are performed with two independent codes, both implementing the Spectral Element Method. They rely on a robust, semi-automated, mesh design strategy together with a simple homogenization procedure to define a smooth velocity model of the basin. Our simulations are accurate up to 4 Hz, and include the effects of surface topography and of intrinsic attenuation. Two kinds of simulations are performed: (1) direct simulations of the surface ground motion for real regional events having various back azimuth with respect to the center of the basin; (2) reciprocity-based calculations where the ground motion due to 980 different seismic sources is computed at a few stations in the basin. In the reciprocity-based calculations, we consider epicentral distances varying from 2.5 km to 40 km, source depths from 1 km to 15 km and we span the range of possible back-azimuths with a 10 degree bin. We will present some results showing (1) the sensitivity of ground motion parameters to the location and focal mechanism of the seismic sources; and (2) the variability of the amplification caused by site effects, as measured by standard spectral ratios, to the source characteristics

  1. Strong ground motion simulation during the November 1759 Earthquake along Serghaya Fault in the metropolitan of Damascus, Syria

    NASA Astrophysics Data System (ADS)

    Zaineh, Hussam Eldein; Yamanaka, Hiroaki; Dhakal, Yadab Prasad; Dakkak, Rawaa; Daoud, Mohamad

    2013-10-01

    The seismic hazard potential for metropolitan of Damascus, Syria is mainly controlled by earthquakes along Serghaya Fault which is a branch of Dead Sea Fault System. In this study, strong ground motion due to the November 1759 Earthquake along the fault of Serghaya was estimated with a numerical simulation technique. In the simulation, the Kostrov-like slip-velocity function was used as an input to the discrete wave number method to simulate the strong ground motions in a broadband frequency range. In order to model the incoherent rupture propagation which can excite large high-frequency waves, random numbers are added to arrival time of circular rupture front. MMI intensities calculated from the synthetic ground motions are compared with the observed values by Ambraseys and Barazangi (J Geophys Res 94:4007-4013, 1989). The calculated intensities are in good agreement with the observed ones at the most sites that validate appropriateness of the proposed source model. The PGA and PGV in the eastern region of Damascus city are higher than those in the western region due to the effects of local site amplification. The simulated high-frequency (1.0-6.0 Hz) ground motions for the sites in the Damascus city are higher than the design requirements defined by the Syrian building code. Furthermore, the simulated high-frequency ground motions for sites in the focal region are bigger than the design requirements in the case of the near-fault factors and are not considered. That demonstrates the appropriateness of considering the near-fault factors for a site near the focal region as introduced by the new building code.

  2. Significance of rotating ground motions on nonlinear behavior of symmetric and asymmetric buildings in near fault sites

    USGS Publications Warehouse

    Kalkan, Erol; Juan Carlos Reyes

    2012-01-01

    Building codes in the U.S. require at least two horizontal ground motion components for three-dimensional (3D) response history analysis (RHA) of structures. For sites within 5 km of an active fault, these records should be rotated to fault-normal/fault-parallel (FN/FP) directions, and two RHA analyses should be performed separately (when FN and then FP are aligned with transverse direction of the structural axes). It is assumed that this approach will lead to two sets of responses that envelope the range of possible responses over all non-redundant rotation angles. This assumption is examined here using 3D computer models of a single-story structure having symmetric (that is, torsionally-stiff) and asymmetric (that is, torsionally flexible) layouts subjected to an ensemble of bi-directional near-fault strong ground motions with and without apparent velocity pulses. In this parametric study, the elastic vibration period of the structures is varied from 0.2 to 5 seconds, and yield strength reduction factors R is varied from a value that leads to linear-elastic design to 3 and 5. The influence that the rotation angle of the ground motion has on several engineering demand parameters (EDPs) is examined in linear-elastic and nonlinear-inelastic domains to form a benchmark for evaluating the use of the FN/FP directions as well as the maximum-direction (MD) ground motion, a new definition of horizontal ground motions for use in the seismic design of structures according to the 2009 NEHRP Provisions and Commentary.

  3. Modelling of Strong Ground Motions from 1991 Uttarkashi, India, Earthquake Using a Hybrid Technique

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Teotia, S. S.; Sriram, V.

    2011-10-01

    We present a simple and efficient hybrid technique for simulating earthquake strong ground motion. This procedure is the combination of the techniques of envelope function (M idorikawa et al. Tectonophysics 218:287-295, 1993) and composite source model (Z eng et al. Geophys Res Lett 21:725-728, 1994). The first step of the technique is based on the construction of the envelope function of the large earthquake by superposition of envelope functions for smaller earthquakes. The smaller earthquakes (sub-events) of varying sizes are distributed randomly, instead of uniform distribution of same size sub-events, on the fault plane. The accelerogram of large event is then obtained by combining the envelope function with a band-limited white noise. The low-cut frequency of the band-limited white noise is chosen to correspond to the corner frequency for the target earthquake magnitude and the high-cut to the Boore's f max or a desired frequency for the simulation. Below the low-cut frequency, the fall-off slope is 2 in accordance with the ω2 earthquake source model. The technique requires the parameters such as fault area, orientation of the fault, hypocenter, size of the sub-events, stress drop, rupture velocity, duration, source-site distance and attenuation parameter. The fidelity of the technique has been demonstrated by successful modeling of the 1991 Uttarkashi, Himalaya earthquake (Ms 7). The acceptable locations of the sub-events on the fault plane have been determined using a genetic algorithm. The main characteristics of the simulated accelerograms, comprised of the duration of strong ground shaking, peak ground acceleration and Fourier and response spectra, are, in general, in good agreement with those observed at most of the sites. At some of the sites the simulated accelerograms differ from observed ones by a factor of 2-3. The local site geology and topography may cause such a difference, as these effects have not been considered in the present technique. The

  4. Integrating nonlinear site effects in broadband ground motion models: Observations and simulations in the Los Angeles basin

    NASA Astrophysics Data System (ADS)

    Assimaki, D.; Steidl, J.; Li, W.

    2006-12-01

    Site-specific ground response analyses to strong seismic motion are currently required for the design of new components of the civil infrastructure on deep and/or soft sedimentary deposits, which prevail in many urban areas of moderate to high seismic risk in the US such as the Los Angeles basin. In these cases, it is necessary to arrive at realistic predictions of the nonlinear soil behavior, which require elaborate analyses to be employed that are associated, however, with considerable cost and effort. Currently, uncertainties exist regarding the methodology to be employed, the level of sophistication required that determines the number of input parameters, and the development of these parameters for implementation. These difficulties, further aggravated by the lack of well-documented validation studies, have thus far prohibited the integration of nonlinear analysis procedures in broadband ground motion simulations. We here present the parametric investigation of recorded and simulated ground motion time-histories for selected sites in the Los Angeles basin, conducted to examine the variability in ground response estimation as a function of the employed nonlinear soil model complexity, and the extent of geotechnical data availability in the near-surface. For this purpose, weak motion waveform inversion is first employed at selected sites in the basin, in absence of the necessary detailed low-strain dynamic soil property distribution in the near surface. Successively, the corresponding one-dimensional (1D) crustal velocity profiles are depicted at these locations based on the SCEC Community Velocity Model, and synthetic ground motion simulations are conducted for the rupture of a wide range of strike-slip fault geometries by means of the hybrid low/high-frequency method with correlated random source parameters. The lack of multiple strong motion seismic data at these sites necessitates the use of simulated ground motion time-histories for the generation of a

  5. Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge

    SciTech Connect

    Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc

    2008-07-08

    Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures.

  6. Development of Optimal Viscous Dampers for RC Structures in Near Field Ground Motions

    SciTech Connect

    Puthanpurayil, Arun M.; Reynolds, Paul

    2008-07-08

    Recent researches show that more than 50% of the economic loss in earthquakes is due to damage of non-structural elements: $8 billion loss in the 1989 Loma Prieta earthquake and $18.5 billion in the 1994 Northridge earthquake. An approach to reduce the economic loss during a seismic event without compromising the structural safety aspect is to incorporate special mechanical devices like fluid viscous dampers in the parent structural system. A recent study carried out to assess the efficacy of viscous dampers in reducing nonstructural damage of low, medium and high rise structures shows that; linear dampers are well suited for low rise category whereas the medium and high rise category requires nonlinear dampers. In this paper an analytical approach is adopted to derive the optimal combination of damper design parameters for all the three categories of structure subjected to near field ground motion. Linear time history analysis by direct time integration was carried out for the linear viscous dampers, while the parameters of the nonlinear viscous dampers were obtained using nonlinear modal time history analysis (Fast Nonlinear analysis). The results of the study are presented in the form of a set of design curves which can be used for the initial selection of parameters for Damper design.

  7. A global earthquake discrimination scheme to optimize ground-motion prediction equation selection

    USGS Publications Warehouse

    Garcia, Daniel; Wald, David J.; Hearne, Michael

    2012-01-01

    We present a new automatic earthquake discrimination procedure to determine in near-real time the tectonic regime and seismotectonic domain of an earthquake, its most likely source type, and the corresponding ground-motion prediction equation (GMPE) class to be used in the U.S. Geological Survey (USGS) Global ShakeMap system. This method makes use of the Flinn–Engdahl regionalization scheme, seismotectonic information (plate boundaries, global geology, seismicity catalogs, and regional and local studies), and the source parameters available from the USGS National Earthquake Information Center in the minutes following an earthquake to give the best estimation of the setting and mechanism of the event. Depending on the tectonic setting, additional criteria based on hypocentral depth, style of faulting, and regional seismicity may be applied. For subduction zones, these criteria include the use of focal mechanism information and detailed interface models to discriminate among outer-rise, upper-plate, interface, and intraslab seismicity. The scheme is validated against a large database of recent historical earthquakes. Though developed to assess GMPE selection in Global ShakeMap operations, we anticipate a variety of uses for this strategy, from real-time processing systems to any analysis involving tectonic classification of sources from seismic catalogs.

  8. Soil amplification maps for estimating earthquake ground motions in the Central US

    USGS Publications Warehouse

    Bauer, R.A.; Kiefer, J.; Hester, N.

    2001-01-01

    The State Geologists of the Central United States Earthquake Consortium (CUSEC) are developing maps to assist State and local emergency managers and community officials in evaluating the earthquake hazards for the CUSEC region. The state geological surveys have worked together to produce a series of maps that show seismic shaking potential for eleven 1 X 2 degree (scale 1:250 000 or 1 in. ??? 3.9 miles) quadrangles that cover the high-risk area of the New Madrid Seismic Zone in eight states. Shear wave velocity values for the surficial materials were gathered and used to classify the soils according to their potential to amplify earthquake ground motions. Geologic base maps of surficial materials or 3-D material maps, either existing or produced for this project, were used in conjunction with shear wave velocities to classify the soils for the upper 15-30 m. These maps are available in an electronic form suitable for inclusion in the federal emergency management agency's earthquake loss estimation program (HAZUS). ?? 2001 Elsevier Science B.V. All rights reserved.

  9. Monitoring volcanic activity using correlation patterns between infrasound and ground motion

    NASA Astrophysics Data System (ADS)

    Ichihara, M.; Takeo, M.; Yokoo, A.; Oikawa, J.; Ohminato, T.

    2012-02-01

    This paper presents a simple method to distinguish infrasonic signals from wind noise using a cross-correlation function of signals from a microphone and a collocated seismometer. The method makes use of a particular feature of the cross-correlation function of vertical ground motion generated by infrasound, and the infrasound itself. Contribution of wind noise to the correlation function is effectively suppressed by separating the microphone and the seismometer by several meters because the correlation length of wind noise is much shorter than wavelengths of infrasound. The method is applied to data from two recent eruptions of Asama and Shinmoe-dake volcanoes, Japan, and demonstrates that the method effectively detects not only the main eruptions, but also minor activity generating weak infrasound hardly visible in the wave traces. In addition, the correlation function gives more information about volcanic activity than infrasound alone, because it reflects both features of incident infrasonic and seismic waves. Therefore, a graphical presentation of temporal variation in the cross-correlation function enables one to see qualitative changes of eruptive activity at a glance. This method is particularly useful when available sensors are limited, and will extend the utility of a single microphone and seismometer in monitoring volcanic activity.

  10. Monitoring volcanic activities using correlation patterns between infrasound and ground motion

    NASA Astrophysics Data System (ADS)

    Ichihara, M.; Takeo, M.; Yokoo, A.

    2012-04-01

    This paper presents a simple method to distinguish infrasonic signals from wind noise using a cross-correlation function of signals from a microphone and a co-located seismometer. The method makes use of a particular feature of the cross-correlation function of vertical ground motion generated by infrasound, and the infrasound itself. Contribution of wind noise to the correlation function is effectively suppressed by separating the microphone and the seismometer by several meters because the correlation length of wind noise is much shorter than wavelengths of infrasound. The method is tested with data from volcanoes, and demonstrates that the method effectively detects not only the main eruptions, but also minor activity generating weak infrasound hardly visible in the wave traces. In addition, the correlation function gives more information about volcanic activity than infrasound alone. The correlation pattern changes when the spectral feature of the infrasound and/or the seismic wave changes and the relative strength of infrasound and seismic wave changes, both of which are expected to be accompanied by change in eruptive activity. Therefore, a graphical presentation of temporal variation in the cross-correlation function enables to see qualitative changes of eruptive activities at a glance. This method is particularly useful when available sensors are limited, and will extend the utility of a single microphone and seismometer in monitoring and understanding volcanic activity. The method is used to analyze sequences of two recent eruptions of Asama and Shinmoe-dake volcanoes, Japan.

  11. Slip reactivation during the 2011 Tohoku earthquake: Dynamic rupture and ground motion simulations

    NASA Astrophysics Data System (ADS)

    Galvez, P.; Dalguer, L. A.

    2013-12-01

    The 2011 Mw9 Tohoku earthquake generated such as vast geophysical data that allows studying with an unprecedented resolution the spatial-temporal evolution of the rupture process of a mega thrust event. Joint source inversion of teleseismic, near-source strong motion and coseismic geodetic data , e.g [Lee et. al, 2011], reveal an evidence of slip reactivation process at areas of very large slip. The slip of snapshots of this source model shows that after about 40 seconds the big patch above to the hypocenter experienced an additional push of the slip (reactivation) towards the trench. These two possible repeating slip exhibited by source inversions can create two waveform envelops well distinguished in the ground motion pattern. In fact seismograms of the KiK-Net Japanese network contained this pattern. For instance a seismic station around Miyagi (MYGH10) has two main wavefronts separated between them by 40 seconds. A possible physical mechanism to explain the slip reactivation could be a thermal pressurization process occurring in the fault zone. In fact, Kanamori & Heaton, (2000) proposed that for large earthquakes frictional melting and fluid pressurization can play a key role of the rupture dynamics of giant earthquakes. If fluid exists in a fault zone, an increase of temperature can rise up the pore pressure enough to significantly reduce the frictional strength. Therefore, during a large earthquake the areas of big slip persuading strong thermal pressurization may result in a second drop of the frictional strength after reaching a certain value of slip. Following this principle, we adopt for slip weakening friction law and prescribe a certain maximum slip after which the friction coefficient linearly drops down again. The implementation of this friction law has been done in the latest unstructured spectral element code SPECFEM3D, Peter et. al. (2012). The non-planar subduction interface has been taken into account and place on it a big asperity patch inside

  12. Ground-motion Attenuation Relation from Strong-motion Records of the 2001 Mw 7.7 Bhuj Earthquake Sequence (2001-2006), Gujarat, India

    NASA Astrophysics Data System (ADS)

    Mandal, Prantik; Kumar, N.; Satyamurthy, C.; Raju, I. P.

    2009-03-01

    Predictive relations are developed for peak ground acceleration (PGA) from the engineering seismoscope (SRR) records of the 2001 Mw 7.7 Bhuj earthquake and 239 strong-motion records of 32 significant aftershocks of 3.1 ≤ Mw ≤ 5.6 at epicentral distances of 1 ≤ R ≤ 288 km. We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relation for peak horizontal acceleration in the Kachchh seismic zone, Gujarat. This new analysis uses the Joyner-Boore’s method for a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. The resulting attenuation equation is, eqalign{ ln ({Y}) = -7.9527 + 1.4043 {M}_{{W}} - ln left( {{r}_{{jb}}2 + 19.822} right)^{1/2} - 0.0682 {S} ŗ{for} 3.1 { < M}_{{W}} le 7.7quad quad {std}. {dev}. left(σ right): ± 0.8243, ŗ} where, Y is peak horizontal acceleration in g, Mw is moment magnitude, rjb is the closest distance to the surface projection of the fault rupture in kilometers, and S is a variable taking the values of 0 and 1 according to the local site geology. S is 0 for a rock site, and, S is 1 for a soil site. The relation differs from previous work in the improved reliability of input parameters and large numbers of strong-motion PGA data recorded at short distances (0-50 km) from the source. The relation is in demonstrable agreement with the recorded strong-ground motion data from earthquakes of Mw 3.5, 4.1, 4.5, 5.6, and 7.7. There are insufficient data from the Kachchh region to adequately judge the relation for the magnitude range 5.7 ≤ Mw ≤ 7.7. But, our ground-motion prediction model shows a reasonable correlation with the PGA data of the 29 March, 1999 Chamoli main shock (Mw 6.5), validating our ground-motion attenuation model for an Mw6.5 event. However, our ground-motion prediction shows no correlation with the PGA data of the 10 December, 1967 Koyna main shock (Mw 6.3). Our ground-motion predictions

  13. Comparisons of ground motions from the 1999 Chi-Chi, earthquake with empirical predictions largely based on data from California

    USGS Publications Warehouse

    Boore, D.M.

    2001-01-01

    This article has the modest goal of comparing the ground motions recorded during the 1999 Chi-Chi, Taiwan, mainshock with predictions from four empirical-based equations commonly used for western North America; these empirical predictions are largely based on data from California. Comparisons are made for peak acceleration and 5%-damped response spectra at periods between 0.1 and 4 sec. The general finding is that the Chi-Chi ground motions are smaller than those predicted from the empirically based equations for periods less than about 1 sec by factors averaging about 0.4 but as small as 0.26 (depending on period, on which equation is used, and on whether the sites are assumed to be rock or soil). There is a trend for the observed motions to approach or even exceed the predicted motions for longer periods. Motions at similar distances (30-60 km) to the east and to the west of the fault differ dramatically at periods between about 2 and 20 sec: Long-duration wave trains are present on the motions to the west, and when normalized to similar amplitudes at short periods, the response spectra of the motions at the western stations are as much as five times larger than those of motions from eastern stations. The explanation for the difference is probably related to site and propagation effects; the western stations are on the Coastal Plain, whereas the eastern stations are at the foot of young and steep mountains, either in the relatively narrow Longitudinal Valley or along the eastern coast-the sediments underlying the eastern stations are probably shallower and have higher velocity than those under the western stations.

  14. Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV

    SciTech Connect

    I. Wong

    2004-11-05

    This report describes a site-response model and its implementation for developing earthquake ground motion input for preclosure seismic design and postclosure assessment of the proposed geologic repository at Yucca Mountain, Nevada. The model implements a random-vibration theory (RVT), one-dimensional (1D) equivalent-linear approach to calculate site response effects on ground motions. The model provides results in terms of spectral acceleration including peak ground acceleration, peak ground velocity, and dynamically-induced strains as a function of depth. In addition to documenting and validating this model for use in the Yucca Mountain Project, this report also describes the development of model inputs, implementation of the model, its results, and the development of earthquake time history inputs based on the model results. The purpose of the site-response ground motion model is to incorporate the effects on earthquake ground motions of (1) the approximately 300 m of rock above the emplacement levels beneath Yucca Mountain and (2) soil and rock beneath the site of the Surface Facilities Area. A previously performed probabilistic seismic hazard analysis (PSHA) (CRWMS M&O 1998a [DIRS 103731]) estimated ground motions at a reference rock outcrop for the Yucca Mountain site (Point A), but those results do not include these site response effects. Thus, the additional step of applying the site-response ground motion model is required to develop ground motion inputs that are used for preclosure and postclosure purposes.

  15. Long-Period Strong Ground Motions Having Fired Large Oil Storage Tanks During the 2003 Tokachi-Oki, Japan, Earthquake

    NASA Astrophysics Data System (ADS)

    Hatayama, K.

    2005-12-01

    The 2003 Tokachi-oki, Japan, earthquake (Mw8.0; Japan Meteorological Agency, 2003) generated large-amplitude long-period (5 to 8 sec) strong ground motions in the Yufutsu plain, Hokkaido, Japan that is about 200 km away from the epicenter. Those motions excited big sloshing in many large oil storage tanks located on the plain and the sloshing caused two tank fires and several floating roofs to sink. Japanese nation-wide strong-motion observation networks have provided us with the first data set consisting of densely sampled strong ground motions that are rich in long-period components. This data set clearly showed that the large long-period motions were not observed before the waves entering the plain, i.e. the Yufutsu plain grew the long-period ground motions (Koketsu et al., 2005). The high density of spatial sampling can also show the spatial distribution of strength of long-period motions in the plain and their propagation there. We show by some contour maps of velocity responses that the strongest long-period shaking in the Yufutsu plain was observed around the downtown area of the Tomakomai city where the damage to oil tanks was more severe than any other areas. The isochrone of peaks of envelopes suggests a possibility that the long-period wave trains were focusing into the downtown from different directions. In order to study the excitation and the propagation process of long-period motions in the Yufutsu plain, an attempt was made to explore its deep sediment-bedrock structure by means of long-period microtremor array observations (Kanno et al., 2005). Relying on their resultant S-wave velocity profiles, we try to reproduce the features of the long-period motions observed there during the 2003 Tokachi-oki earthquake by making numerical simulations of 2-D seismic wave-fields by means of the finite difference method. To date we have succeeded in reproducing qualitatively the observed phenomena that the amplitude of long-period motions in the downtown area of

  16. GPS monitoring of vertical ground motion in northern Ardenne Eifel: five campaigns (1999 2003) of the HARD project

    NASA Astrophysics Data System (ADS)

    Demoulin, A.; Campbell, J.; Wulf, A. De.; Muls, A.; Arnould, R.; Görres, B.; Fischer, D.; Kötter, T.; Brondeel, M.; Damme, D. Van.; Jacqmotte, J. M.

    2005-09-01

    We present the HARD project of GPS monitoring of vertical ground motion in NE Ardenne and Eifel (western Europe). Its main purposes are to get a better insight into the present-day rates of vertical ground motion in intraplate settings and to identify the various causes of these motions. Since 1999, we have carried out yearly campaigns of simultaneous GPS measurements at 12 sites situated so as to sample the different tectonic subunits of the study area and especially to record potential displacements across the seismogenic Hockai fault zone. Five campaigns (1999 2003) have been processed currently. Key issues of the data processing with the Gamit software are discussed and first results are presented. Though temporally consistent in many cases, the obtained vertical motion rates are spatially highly variable. They are also much too high (several mm/year) to support a tectonic interpretation, and a long-term influence of groundwater level variations is proposed to account for the observed motions. This influence should be distinguished from seasonal variations and from inter-survey variations linked to the varying degree of soil and subsoil drying off during the successive spring surveys.

  17. Procedure of evaluating parameters of inland earthquakes caused by long strike-slip faults for ground motion prediction

    NASA Astrophysics Data System (ADS)

    Ju, Dianshu; Dan, Kazuo; Fujiwara, Hiroyuki; Morikawa, Nobuyuki

    2016-04-01

    We proposed a procedure of evaluating fault parameters of asperity models for predicting strong ground motions from inland earthquakes caused by long strike-slip faults. In order to obtain averaged dynamic stress drops, we adopted the formula obtained by dynamic fault rupturing simulations for surface faults of the length from 15 to 100 km, because the formula of the averaged static stress drops for circular cracks, commonly adopted in existing procedures, cannot be applied to surface faults or long faults. The averaged dynamic stress drops were estimated to be 3.4 MPa over the entire fault and 12.2 MPa on the asperities, from the data of 10 earthquakes in Japan and 13 earthquakes in other countries. The procedure has a significant feature that the average slip on the seismic faults longer than about 80 km is constant, about 300 cm. In order to validate our proposed procedure, we made a model for a 141 km long strike-slip fault by our proposed procedure for strike-slip faults, predicted ground motions, and showed that the resultant motions agreed well with the records of the 1999 Kocaeli, Turkey, earthquake (Mw 7.6) and with the peak ground accelerations and peak ground velocities by the GMPE of Si and Midorikawa (1999).

  18. Simulation of Strong Ground Motion for the 7.6Mw Kashmir Earthquake Occurred on 8 Oct 2005

    NASA Astrophysics Data System (ADS)

    Naveed, A.; Muhammad sohail, K.

    2015-12-01

    The Mw 7.6 Kashmir earthquake which struck the northern area of Pakistan , the Kashmir region on 8 October 2005.The epicenter was located 18km north-northeast of Muzaffarabad, with a focal depth of 26km and it occurred in the Hazara-kashmir syntaxial bend near Main Mantle Thrust (MMT). This is one of the most devastating earthquakes occurred along Himalayan Arc and brought more than 80,000 deaths and more than 5.2 billion USD economical loss. The earthquake had duration of 25s and 75km rupture length along the surface. In order to investigate the strong motion caused by this earthquake, we simulate the Kashmir earthquake by the Curved grid finite difference method (CG-FDM). The finite-fault rupture, real topography variations and modified crustal model are considered. Simulated results are compared with available records, showing good mutual agreement between the synthetic and observed ground motions. According to the Pakistan Meteorological Department (PMD), the intensity of four observed points had reached scale IX, whereas our simulated results show those points are located in the regions with our predicted intensity scale IX or VIII. Peak Ground Acceleration (PGA) and Peak ground velocity (PGV) are most important parameters for hazard analysis, and our results are sufficiently coincide with their observed values. Finally, we also discuss the significant effect of surface topography on ground motion resulting by the Earthquake.

  19. Estimated ground motion from the 1994 Northridge, California, earthquake at the site of interstate 10 and La Cienega Boulevard bridge collapse, West Los Angeles, California

    USGS Publications Warehouse

    Boore, D.M.; Gibbs, J.F.; Joyner, W.B.; Tinsley, J.C.; Ponti, D.J.

    2003-01-01

    We have estimated ground motions at the site of a bridge collapse during the 1994 Northridge, California, earthquake. The estimated motions are based on correcting motions recorded during the mainshock 2.3 km from the collapse site for the relative site response of the two sites. Shear-wave slownesses and damping based on analysis of borehole measurements at the two sites were used in the site response analysis. We estimate that the motions at the collapse site were probably larger, by factors ranging from 1.2 to 1.6, than at the site at which the ground motion was recorded, for periods less than about 1 sec.

  20. Hybrid broadband Ground Motion simulation based on a dynamic rupture model of the 2011 Mw 9.0 Tohoku earthquake.

    NASA Astrophysics Data System (ADS)

    Galvez, P.; Somerville, P.; Bayless, J.; Dalguer, L. A.

    2015-12-01

    The rupture process of the 2011 Tohoku earthquake exhibits depth-dependent variations in the frequency content of seismic radiation from the plate interface. This depth-varying rupture property has also been observed in other subduction zones (Lay et al, 2012). During the Tohoku earthquake, the shallow region radiated coherent low frequency seismic waves whereas the deeper region radiated high frequency waves. Several kinematic inversions (Suzuki et al, 2011; Lee et al, 2011; Bletery et al, 2014; Minson et al, 2014) detected seismic waves below 0.1 Hz coming from the shallow depths that produced slip larger than 40-50 meters close to the trench. Using empirical green functions, Asano & Iwata (2012), Kurahashi and Irikura (2011) and others detected regions of strong ground motion radiation at frequencies up to 10Hz located mainly at the bottom of the plate interface. A recent dynamic model that embodies this depth-dependent radiation using physical models has been developed by Galvez et al (2014, 2015). In this model the rupture process is modeled using a linear weakening friction law with slip reactivation on the shallow region of the plate interface (Galvez et al, 2015). This model reproduces the multiple seismic wave fronts recorded on the Kik-net seismic network along the Japanese coast up to 0.1 Hz as well as the GPS displacements. In the deep region, the rupture sequence is consistent with the sequence of the strong ground motion generation areas (SMGAs) that radiate high frequency ground motion at the bottom of the plate interface (Kurahashi and Irikura, 2013). It remains challenging to perform ground motions fully coupled with a dynamic rupture up to 10 Hz for a megathrust event. Therefore, to generate high frequency ground motions, we make use of the stochastic approach of Graves and Pitarka (2010) but add to the source spectrum the slip rate function of the dynamic model. In this hybrid-dynamic approach, the slip rate function is windowed with Gaussian

  1. Ground Motion Prediction Equations for the Central and Eastern United States

    NASA Astrophysics Data System (ADS)

    Seber, D.; Graizer, V.

    2015-12-01

    New ground motion prediction equations (GMPE) G15 model for the Central and Eastern United States (CEUS) is presented. It is based on the modular filter based approach developed by Graizer and Kalkan (2007, 2009) for active tectonic environment in the Western US (WUS). The G15 model is based on the NGA-East database for the horizontal peak ground acceleration and 5%-damped pseudo spectral acceleration RotD50 component (Goulet et al., 2014). In contrast to active tectonic environment the database for the CEUS is not sufficient for creating purely empirical GMPE covering the range of magnitudes and distances required for seismic hazard assessments. Recordings in NGA-East database are sparse and cover mostly range of M<6.0 with limited amount of near-fault recordings. The functional forms of the G15 GMPEs are derived from filters—each filter represents a particular physical phenomenon affecting the seismic wave radiation from the source. Main changes in the functional forms for the CEUS relative to the WUS model (Graizer and Kalkan, 2015) are a shift of maximum frequency of the acceleration response spectrum toward higher frequencies and an increase in the response spectrum amplitudes at high frequencies. Developed site correction is based on multiple runs of representative VS30 profiles through SHAKE-type equivalent-linear programs using time histories and random vibration theory approaches. Site amplification functions are calculated for different VS30 relative to hard rock definition used in nuclear industry (Vs=2800 m/s). The number of model predictors is limited to a few measurable parameters: moment magnitude M, closest distance to fault rupture plane R, average shear-wave velocity in the upper 30 m of the geological profile VS30, and anelastic attenuation factor Q0. Incorporating anelastic attenuation Q0 as an input parameter allows adjustments based on the regional crustal properties. The model covers the range of magnitudes 4.0

  2. Precise ground motion measurements to support multi-hazard analysis in Jakarta

    NASA Astrophysics Data System (ADS)

    Koudogbo, Fifamè; Duro, Javier; Garcia Robles, Javier; Abidin, Hasanuddin Z.

    2015-04-01

    Jakarta is the capital of Indonesia and is home to approximately 10 million people on the coast of the Java Sea. The Capital District of Jakarta (DKI) sits in the lowest lying areas of the basin. Its topography varies, with the northern part just meters above current sea level and lying on a flood plain. Subsequently, this portion of the city frequently floods. Flood events have been increasing in severity during the past decade. The February 2007 event inundated 235 Km2 (about 36%) of the city, by up to seven meters in some areas. This event affected more than 2.6 million people; the estimated financial and economic losses from this event amounted to US900 million [1][2]. Inundations continue to occur under any sustained rainfall conditions. Flood events in Jakarta are expected to become more frequent in coming years, with a shift from previously slow natural processes with low frequency to a high frequency process resulting in severe socio-economic damage. Land subsidence in Jakarta results in increased vulnerability to flooding due to the reduced gravitational capacity to channel storm flows to the sea and an increased risk of tidal flooding. It continues at increasingly alarming rates, principally caused by intensive deep groundwater abstraction [3]. Recent studies have found typical subsidence rates of 7.5-10 cm a year. In localized areas of north Jakarta subsidence in the range 15-25 cm a year is occurring which, if sustained, would result in them sinking to 4-5 m below sea level by 2025 [3]. ALTAMIRA INFORMATION, company specialized in ground motion monitoring, has developed GlobalSARTM, which combines several processing techniques and algorithms based on InSAR technology, to achieve ground motion measurements with millimetric precision and high accuracy [4]. Within the RASOR (Rapid Analysis and Spatialisation and Of Risk) project, ALTAMIRA INFORMATION will apply GlobalSARTM to assess recent land subsidence in Jakarta, based on the processing of Very High

  3. Free-field ground motions for the nonproliferation experiment: Preliminary comparisons with nearby nuclear events

    SciTech Connect

    Olsen, K.H.; Peratt, A.L.

    1994-06-01

    Since 1987, we have installed fixed arrays of tri-axial accelerometers in the fire-field near the shot horizons for low-yield ({le} 20 kt) nuclear events in the N-tunnel complex beneath Rainier Mesa. For the Nonproliferation Experiment (NPE) we augmented the array to achieve 23 free-field stations. Goals are: (a) to examine robustness and stability of various free-field source function estimates -- e.g., reduced displacement potentials (RDP) and spectra; (b) to compare close-in with regional estimates to test whether detailed close-in free-field and/or surface ground motion data can improve predictability of regional-teleseismic source functions; (c) to provide experimental data for checking two-dimensional numerical simulations. We report preliminary comparisons between experimental free-field data for NPE (1993) and three nearby nuclear events (MISTY ECHO, 1988; MINERAL QUARRY, 1990; HUNTERS TROPHY, 1992). All four working points are within 1 km of each other in the same wet tuff bed, thus reducing concerns about possible large differences in material properties between widely separated shots. Initial comparison of acceleration and velocity seismograms for the four events reveals: (1) There is a large departure from the spherical symmetry commonly assumed in analytic treatments of source theory; both vertical and tangential components are surprisingly large. (2) All shots show similar first-peak particle-velocity amplitude decay rates suggesting significant attenuation even in the supposedly purely elastic region. (3) Sharp (>20 Hz) arrivals are not observed at tunnel level from near-surface pP reflections or spall-closure sources -- but broadened peaks are seen that suggest more diffuse reflected energy from the surface and from the Paleozoic limestone basement below tunnel level.

  4. An Arduino project to record ground motion and to learn on earthquake hazard at high school

    NASA Astrophysics Data System (ADS)

    Saraò, Angela; Barnaba, Carla; Clocchiatti, Marco; Zuliani, David

    2015-04-01

    Through a multidisciplinary work that integrates Technology education with Earth Sciences, we implemented an educational program to raise the students' awareness of seismic hazard and to disseminate good practices of earthquake safety. Using free software and low-cost open hardware, the students of a senior class of the high school Liceo Paschini in Tolmezzo (NE Italy) implemented a seismograph using the Arduino open-source electronics platform and the ADXL345 sensors to emulate a low cost seismometer (e.g. O-NAVI sensor of the Quake-Catcher Network, http://qcn.stanford.edu). To accomplish their task the students were addressed to use the web resources for technical support and troubleshooting. Shell scripts, running on local computers under Linux OS, controlled the process of recording and display data. The main part of the experiment was documented using the DokuWiki style. Some propaedeutic lessons in computer sciences and electronics were needed to build up the necessary skills of the students and to fill in the gap of their background knowledge. In addition lectures by seismologists and laboratory activity allowed the class to exploit different aspects of the physics of the earthquake and particularly of the seismic waves, and to become familiar with the topics of seismic hazard through an inquiry-based learning. The Arduino seismograph achieved can be used for educational purposes and it can display tremors on the local network of the school. For sure it can record the ground motion due to a seismic event that can occur in the area, but further improvements are necessary for a quantitative analysis of the recorded signals.

  5. Three-dimensional ground-motion simulations of earthquakes for the Hanford area, Washington

    USGS Publications Warehouse

    Frankel, Arthur; Thorne, Paul; Rohay, Alan

    2014-01-01

    This report describes the results of ground-motion simulations of earthquakes using three-dimensional (3D) and one-dimensional (1D) crustal models conducted for the probabilistic seismic hazard assessment (PSHA) of the Hanford facility, Washington, under the Senior Seismic Hazard Analysis Committee (SSHAC) guidelines. The first portion of this report demonstrates that the 3D seismic velocity model for the area produces synthetic seismograms with characteristics (spectral response values, duration) that better match those of the observed recordings of local earthquakes, compared to a 1D model with horizontal layers. The second part of the report compares the response spectra of synthetics from 3D and 1D models for moment magnitude (M) 6.6–6.8 earthquakes on three nearby faults and for a dipping plane wave source meant to approximate regional S-waves from a Cascadia great earthquake. The 1D models are specific to each site used for the PSHA. The use of the 3D model produces spectral response accelerations at periods of 0.5–2.0 seconds as much as a factor of 4.5 greater than those from the 1D models for the crustal fault sources. The spectral accelerations of the 3D synthetics for the Cascadia plane-wave source are as much as a factor of 9 greater than those from the 1D models. The differences between the spectral accelerations for the 3D and 1D models are most pronounced for sites with thicker supra-basalt sediments and for stations with earthquakes on the Rattlesnake Hills fault and for the Cascadia plane-wave source.

  6. Moment tensor inversion of ground motion from mining-induced earthquakes, Trail Mountain, Utah

    USGS Publications Warehouse

    Fletcher, Joe B.; McGarr, A.

    2005-01-01

    A seismic network was operated in the vicinity of the Trail Mountain mine, central Utah, from the summer of 2000 to the spring of 2001 to investigate the seismic hazard to a local dam from mining-induced events that we expect to be triggered by future coal mining in this area. In support of efforts to develop groundmotion prediction relations for this situation, we inverted ground-motion recordings for six mining-induced events to determine seismic moment tensors and then to estimate moment magnitudes M for comparison with the network coda magnitudes Mc. Six components of the tensor were determined, for an assumed point source, following the inversion method of McGarr (1992a), which uses key measurements of amplitude from obvious features of the displacement waveforms. When the resulting moment tensors were decomposed into implosive and deviatoric components, we found that four of the six events showed a substantial volume reduction, presumably due to coseismic closure of the adjacent mine openings. For these four events, the volume reduction ranges from 27% to 55% of the shear component (fault area times average slip). Radiated seismic energy, computed from attenuation-corrected body-wave spectra, ranged from 2.4 ?? 105 to 2.4 ?? 106 J for events with M from 1.3 to 1.8, yielding apparent stresses from 0.02 to 0.06 MPa. The energy released for each event, approximated as the product of volume reduction and overburden stress, when compared with the corresponding seismic energies, revealed seismic efficiencies ranging from 0.5% to 7%. The low apparent stresses are consistent with the shallow focal depths of 0.2 to 0.6 km and rupture in a low stress/low strength regime compared with typical earthquake source regions at midcrustal depths.

  7. Modeling earthquake ground motion with an earthquake simulation program (EMPSYN) that utilizes empirical Green's functions

    SciTech Connect

    Hutchings, L.

    1992-01-01

    This report outlines a method of using empirical Green's functions in an earthquake simulation program EMPSYN that provides realistic seismograms from potential earthquakes. The theory for using empirical Green's functions is developed, implementation of the theory in EMPSYN is outlined, and an example is presented where EMPSYN is used to synthesize observed records from the 1971 San Fernando earthquake. To provide useful synthetic ground motion data from potential earthquakes, synthetic seismograms should model frequencies from 0.5 to 15.0 Hz, the full wave-train energy distribution, and absolute amplitudes. However, high-frequency arrivals are stochastically dependent upon the inhomogeneous geologic structure and irregular fault rupture. The fault rupture can be modeled, but the stochastic nature of faulting is largely an unknown factor in the earthquake process. The effect of inhomogeneous geology can readily be incorporated into synthetic seismograms by using small earthquakes to obtain empirical Green's functions. Small earthquakes with source corner frequencies higher than the site recording limit f{sub max}, or much higher than the frequency of interest, effectively have impulsive point-fault dislocation sources, and their recordings are used as empirical Green's functions. Since empirical Green's functions are actual recordings at a site, they include the effects on seismic waves from all geologic inhomogeneities and include all recordable frequencies, absolute amplitudes, and all phases. They scale only in amplitude with differences in seismic moment. They can provide nearly the exact integrand to the representation relation. Furthermore, since their source events have spatial extent, they can be summed to simulate fault rupture without loss of information, thereby potentially computing the exact representation relation for an extended source earthquake.

  8. Strong ground motion inferred from liquefaction caused by the 1811-1812 New Madrid, Missouri, earthquakes

    USGS Publications Warehouse

    Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.

    2015-01-01

    Peak ground accelerations (PGAs) in the epicentral region of the 1811–1812 New Madrid, Missouri, earthquakes are inferred from liquefaction to have been no greater than ∼0.35g. PGA is inferred in an 11,380  km2 area in the Lower Mississippi Valley in Arkansas and Missouri where liquefaction was extensive in 1811–1812. PGA was inferred by applying liquefaction probability curves, which were originally developed for liquefaction hazard mapping, to detailed maps of liquefaction by Obermeier (1989). The low PGA is inferred because both a shallow (1.5 m deep) water table and a large moment magnitude (M 7.7) earthquake were assumed in the analysis. If a deep (5.0 m) water table and a small magnitude (M 6.8) earthquake are assumed, the maximum inferred PGA is 1.10g. Both inferred PGA values are based on an assumed and poorly constrained correction for sand aging. If an aging correction is not assumed, then the inferred PGA is no greater than 0.22g. A low PGA value may be explained by nonlinear site response. Soils in the study area have an averageVS30 of 220±15  m/s. A low inferred PGA is consistent with PGA values estimated from ground‐motion prediction equations that have been proposed for the New Madrid seismic zone when these estimates are corrected for nonlinear soil site effects. This application of liquefaction probability curves demonstrates their potential usefulness in paleoseismology.

  9. Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions

    USGS Publications Warehouse

    Atkinson, G.M.; Boore, D.M.

    2003-01-01

    Ground-motion relations for earthquakes that occur in subduction zones are an important input to seismic-hazard analyses in many parts of the world. In the Cascadia region (Washington, Oregon, northern California, and British Columbia), for example, there is a significant hazard from megathrust earthquakes along the subduction interface and from large events within the subducting slab. These hazards are in addition to the hazard from shallow earthquakes in the overlying crust. We have compiled a response spectra database from thousands of strong-motion recordings from events of moment magnitude (M) 5-8.3 occurring in subduction zones around the world, including both interface and in-slab events. The 2001 M 6.8 Nisqually and 1999 M 5.9 Satsop earthquakes are included in the database, as are many records from subduction zones in Japan (Kyoshin-Net data), Mexico (Guerrero data), and Central America. The size of the database is four times larger than that available for previous empirical regressions to determine ground-motion relations for subduction-zone earthquakes. The large dataset enables improved determination of attenuation parameters and magnitude scaling, for both interface and in-slab events. Soil response parameters are also better determined by the data. We use the database to develop global ground-motion relations for interface and in-slab earthquakes, using a maximum likelihood regression method. We analyze regional variability of ground-motion amplitudes across the global database and find that there are significant regional differences. In particular, amplitudes in Cascadia differ by more than a factor of 2 from those in Japan for the same magnitude, distance, event type, and National Earthquake Hazards Reduction Program (NEHRP) soil class. This is believed to be due to regional differences in the depth of the soil profile, which are not captured by the NEHRP site classification scheme. Regional correction factors to account for these differences are

  10. Coupling of Pore Pressure and Ground Motion: Further Studies using Data Recorded at the NEES@UCSB Wildlife Station

    NASA Astrophysics Data System (ADS)

    Seale, S. H.; Lavallee, D.; Archuleta, R. J.; Steidl, J. H.

    2012-12-01

    Pore pressure built up during an earthquake and the hazard associated with soil liquefaction present a major challenge for our society, as has been dramatically illustrated by recent large events (e.g. the 2011 Tohoku-oki, Japan, earthquake). There is consensus among scientists that a better assessment of the liquefaction risk requires a better understanding of the coupling between pore pressure and ground motion time histories. There is a basic need to investigate coupling as a function of the frequency content of the ground motion. The 2010 M7.2 El Mayor-Cucapah event has provided a remarkable opportunity to investigate and model the coupling. The event was well recorded at the NEES@UCSB Wildlife station located 110 km from the hypocenter. The station is equipped with three-component strong-motion accelerometers at the surface and in boreholes at various depths and with pore pressure transducers located in a saturated, liquefiable layer. The recorded pore pressure and ground motion time histories both have frequency content that is a function of time. We have applied a wavelet decomposition technique to the El Mayor ground motion and pore pressure data, looking for a linear relationship between the signals. The analysis shows that the early P-wave accelerations (vertical component) initiate pore pressure response. However, the pore pressure records contain a low-frequency component that dominates the signal with no corresponding low-frequency component in the ground motion signals recorded near-by. Although uncommon, a similar behavior has been also reported in the literature for pore pressure signals recoded during the 1980 Mammoth Lakes, California, earthquake. We have extended this work to the analysis of 4 other seismic events that have induced an increase in pore pressure at WLA. As the response of pore pressure is potentially a local phenomenon, we have restricted our analysis to recordings from the same site. These events include the M5.8 Ocotillo

  11. Simulation of Ground Motion from Strong Earthquakes of Kamchatka Region (1992-1993) at Rock and Soil Sites

    NASA Astrophysics Data System (ADS)

    Pavlenko, O. V.

    2013-04-01

    To estimate the parameters of ground motion in future strong earthquakes, characteristics of radiation and propagation of seismic waves in the Kamchatka region were studied. Regional parameters of radiation and propagation of seismic waves were estimated by comparing simulations of earthquake records with data recorded by stations of the Kamchatka Strong Motion Network. Acceleration time histories of strong earthquakes ( M w = 6.8-7.5, depths 45-55 km) that occurred near the eastern coast of Kamchatka in 1992-1993 were simulated at rock and soil stations located at epicentral distances of 67-195 km. In these calculations, the source spectra and the estimates of frequency-dependent attenuation and geometrical spreading obtained earlier for Kamchatka were used. The local seismic-wave amplification was estimated based on shallow geophysical site investigations and deep crustal seismic explorations, and parameters defining the shapes of the waveforms, the duration, etc. were selected, showing the best-fit to the observations. The estimated parameters of radiation and propagation of seismic waves describe all the studied earthquakes well. Based on the waveforms of the acceleration time histories, models of slip distribution over the fault planes were constructed for the studied earthquakes. Station PET can be considered as a reference rock station having the minimum site effects. The intensity of ground motion at the other studied stations was higher than at PET due to the soil response or other effects, primarily topographic ones. At soil stations INS, AER, and DCH the parameters of soil profiles (homogeneous pyroclastic deposits) were estimated, and nonlinear models of their behavior in the strong motion were constructed. The obtained parameters of radiation and propagation of seismic waves and models of soil behavior can be used for forecasting ground motion in future strong earthquakes in Kamchatka.

  12. Long-Period Ground Motion In the Arabian Gulf From Earthquakes in the Zagros Mountains Thrust Belt

    NASA Astrophysics Data System (ADS)

    Pitarka, A.; Al-Amri, A. M.; Rodgers, A. J.; Pasyanos, M.; Mellors, R. J.

    2013-12-01

    We will compare observed and modeled ground motions recorded in the western shore of the Arabian Gulf from selected earthquakes in the Zagros Mountains region. Exceptionally long-duration seismic waves with very large amplitude, as compared with ground motion prediction equations developed by Campbell and Bozorgnia (2008) and Boore and Atkinson (2006), are found to occur with periods of 2-10 seconds. These long-period waves may have implications for large structures near the Gulf and therefore it is important to understand the cause. In contrast, the short-period content of ground motion (<2s) at long distances is relatively weak. The long-period waves may be due to waveguide effects in the deep sedimentary basin structure of the Arabian Gulf. Therefore, we performed 3D wave propagation simulations using a finite difference method. Several different velocity models of the Gulf, were tested. The simulation results confirm our hypothesis that long period waves with extremely long duration and relatively large amplitudes are caused by the geometry of the basin sedimentary layers. The depth of the earthquakes is also a factor. Combined effects of basin edge geometry with sharp velocity contrast and shallow sources (< 10km) on the east part of the Arabian Gulf can cause large long period ground motion on the west part of the Gulf. The reduced amplitude of the short-period waves is due to wave propagation scattering and attenuation in the shallow sedimentary layers of the Gulf basin. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  13. Identification of ground motion features for high-tech facility under far field seismic waves using wavelet packet transform

    NASA Astrophysics Data System (ADS)

    Huang, Shieh-Kung; Loh, Chin-Hsiung; Chen, Chin-Tsun

    2016-04-01

    Seismic records collected from earthquake with large magnitude and far distance may contain long period seismic waves which have small amplitude but with dominant period up to 10 sec. For a general situation, the long period seismic waves will not endanger the safety of the structural system or cause any uncomfortable for human activity. On the contrary, for those far distant earthquakes, this type of seismic waves may cause a glitch or, furthermore, breakdown to some important equipments/facilities (such as the high-precision facilities in high-tech Fab) and eventually damage the interests of company if the amplitude becomes significant. The previous study showed that the ground motion features such as time-variant dominant frequencies extracted using moving window singular spectrum analysis (MWSSA) and amplitude characteristics of long-period waves identified from slope change of ground motion Arias Intensity can efficiently indicate the damage severity to the high-precision facilities. However, embedding a large hankel matrix to extract long period seismic waves make the MWSSA become a time-consumed process. In this study, the seismic ground motion data collected from broadband seismometer network located in Taiwan were used (with epicenter distance over 1000 km). To monitor the significant long-period waves, the low frequency components of these seismic ground motion data are extracted using wavelet packet transform (WPT) to obtain wavelet coefficients and the wavelet entropy of coefficients are used to identify the amplitude characteristics of long-period waves. The proposed method is a timesaving process compared to MWSSA and can be easily implemented for real-time detection. Comparison and discussion on this method among these different seismic events and the damage severity to the high-precision facilities in high-tech Fab is made.

  14. Quantification of focusing effects of the semi-spherical and semi-cylindrical synclinal basement topography on ground motion characteristics

    NASA Astrophysics Data System (ADS)

    Sahar, D.; Narayan, J. P.

    2016-01-01

    The anomalous damage patterns developed by the focusing of seismic waves due to deep and shallow seated synclinal basement topography were reported during the Northridge earthquake of 1994 and the Nisqually earthquake of 2001, respectively. This paper presents the role of sediment velocity, depth and geometry of the basement topography in basement focusing effects on ground motion characteristics. An increase of amplitude of the mode converted and the diffracted waves with an increase of impedance contrast and curvature of the basement topography was inferred. It is concluded that the basement focusing effect is unaffected by the change of focal length due to the change of either sediment velocity or radius of curvature for a fixed chord length in the absence of sediment damping. Further, under a favourable condition, the focusing of multiples of the transmitted waves may cause much larger amplitude amplification than that caused by the focusing of the transmitted wave itself. Extensive spatial variations in ground motion level were obtained with the change of depth and chord length of the basement topography. A comparative analysis of the responses of semi-spherical basement topography (3D) and semi-cylindrical basement topography (2D) strongly suggests that 1D or 2D response of an area underlain by a 3D depression should not be used in predicting the ground motion.

  15. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    NASA Astrophysics Data System (ADS)

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-02-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals.

  16. Inversion of ground-motion data from a seismometer array for rotation using a modification of Jaeger's method

    USGS Publications Warehouse

    Chi, W.-C.; Lee, W.H.K.; Aston, J.A.D.; Lin, C.J.; Liu, C.-C.

    2011-01-01

    We develop a new way to invert 2D translational waveforms using Jaeger's (1969) formula to derive rotational ground motions about one axis and estimate the errors in them using techniques from statistical multivariate analysis. This procedure can be used to derive rotational ground motions and strains using arrayed translational data, thus providing an efficient way to calibrate the performance of rotational sensors. This approach does not require a priori information about the noise level of the translational data and elastic properties of the media. This new procedure also provides estimates of the standard deviations of the derived rotations and strains. In this study, we validated this code using synthetic translational waveforms from a seismic array. The results after the inversion of the synthetics for rotations were almost identical with the results derived using a well-tested inversion procedure by Spudich and Fletcher (2009). This new 2D procedure can be applied three times to obtain the full, three-component rotations. Additional modifications can be implemented to the code in the future to study different features of the rotational ground motions and strains induced by the passage of seismic waves.

  17. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion.

    PubMed

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green's function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s(2) in the horizontal direction and 0.0917 m/s(2) in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0-7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  18. Regional amplification of ground motion in central Mexico. Results from coda-length magnitude data and preliminary modeling

    NASA Astrophysics Data System (ADS)

    Cárdenas, Martín; Chávez-García, Francisco J.; Gusev, Alexander

    Seismic ground motion in central Mexico is amplified relative to ground motion observed at the same epicentral distance along the Pacific Coast in a frequency band that includes destructive ground motion at Mexico City. Although several hypothesis have been advanced, at present there is no generally accepted explanation of such amplification. We have analyzed coda-length magnitude data reported by Servicio Sismológico Nacional (SSN) for events recorded during 1993 to increase our understanding of the spatial distribution of this phenomenon. Our results indicate that regional amplification: (a) is detected by magnitude residual computed at each station, relative to the average of SSN network;and (b) is likely related to the crustal structure under the central portion of the Transmexican Volcanic Belt (TMVB). Finally, preliminary wave propagation modelling (using SH wave, finite difference method) suggests that crustal heterogeneity is a possible cause of regional amplification. However, if this is so, it is required that both geometry and velocity distribution vary between the coast and Mexico City.

  19. Characterisation of hydraulic head changes and aquifer properties in the London Basin using Persistent Scatterer Interferometry ground motion data

    NASA Astrophysics Data System (ADS)

    Bonì, R.; Cigna, F.; Bricker, S.; Meisina, C.; McCormack, H.

    2016-09-01

    In this paper, Persistent Scatterer Interferometry was applied to ERS-1/2 and ENVISAT satellite data covering 1992-2000 and 2002-2010 respectively, to analyse the relationship between ground motion and hydraulic head changes in the London Basin, United Kingdom. The integration of observed groundwater levels provided by the Environment Agency and satellite-derived displacement time series allowed the estimation of the spatio-temporal variations of the Chalk aquifer storage coefficient and compressibility over an area of ∼1360 km2. The average storage coefficient of the aquifer reaches values of 1 × 10-3 and the estimated average aquifer compressibility is 7.7 × 10-10 Pa-1 and 1.2 × 10-9 Pa-1 for the periods 1992-2000 and 2002-2010, respectively. Derived storage coefficient values appear to be correlated with the hydrogeological setting, where confined by the London Clay the storage coefficient is typically an order of magnitude lower than where the chalk is overlain by the Lambeth Group. PSI-derived storage coefficient estimates agree with the values obtained from pumping tests in the same area. A simplified one-dimensional model is applied to simulate the ground motion response to hydraulic heads changes at nine piezometers. The comparison between simulated and satellite-observed ground motion changes reveals good agreement, with errors ranging between 1.4 and 6.9 mm, and being 3.2 mm on average.

  20. Prediction of ground motion and dynamic stress change in Baekdusan (Changbaishan) volcano caused by a North Korean nuclear explosion

    PubMed Central

    Hong, Tae-Kyung; Choi, Eunseo; Park, Seongjun; Shin, Jin Soo

    2016-01-01

    Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0–7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals. PMID:26884136

  1. Ground Motion Prediction Equations for data recorded in the immediate vicinity of the San Jacinto fault zone

    NASA Astrophysics Data System (ADS)

    Kurzon, I.; Vernon, F. L.; Ben-Zion, Y.

    2011-12-01

    We present a new set of empirical Ground Motion results for horizontal Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) that include data from the immediate vicinity of the San Jacinto fault zone. The results to date are based on earthquakes in the magnitude range of 1 < M < 5.5 recorded by up to 60 stations at distances ranging from the fault zone itself up to 120km. The data are examined and compared against several models of Ground Motion Prediction Equations (GMPE). The New Generation Attenuation (NGA) project was focused on a magnitude range of M > 5 (e.g., Campbell & Bozorgnia 2006, Boore & Atkinson 2006); therefore, our main comparison is with the ShakeMap system results (Quitoriano 2003 for M < 5.3) and with Cua & Heaton (2008) GMPE accounting for a magnitude range of 2 < M < 8. The data employed so far involves several aftershock sequences on small and known fault segments. These constrains allow for better consideration of the path and site effects, including the path in the near vicinity of the source. Therefore, as opposed to most models (using either the epicentral distance for low magnitude events or the closest surface projection of the fault for stronger events) we consider the hypocentral source-receiver distance as controlling both the geometrical spreading and the inelastic path effects. This approach is not only more physical for M < 5 events, but also reveals the upper crustal heterogeneity (< 20km) in the San Jacinto Fault Zone area. The continuing work will focus on incorporating more data as it becomes available, and using the results to develop updated Ground Motion Prediction Equations. The results will be useful for earthquake engineering and for exploring the crustal heterogeneity around active faults.

  2. Expectable Earthquakes and their ground motions in the Van Norman Reservoirs Area

    USGS Publications Warehouse

    Wesson, R.L.; Page, R.A.; Boore, D.M.; Yerkes, R.F.

    1974-01-01

    The upper and lower Van Norman dams, in northwesternmost San Fernando Valley about 20 mi (32 km) northwest of downtown Los Angeles, were severely damaged during the 1971 San Fernando earthquake. An investigation of the geologic-seismologic setting of the Van Norman area indicates that an earthquake of at least M 7.7 may be expected in the Van Norman area. The expectable transitory effects in the Van Norman area of such an earthquake are as follows: peak horizontal acceleration of at least 1.15 g, peak velocity of displacement of 4.43 ft/sec (135 cm/sec), peak displacement of 2.3 ft (70 cm), and duration of shaking at accelerations greater than 0.05 g, 40 sec. A great earthquake (M 8+) on the San Andreas fault, 25 mi distant, also is expectable. Transitory effects in the Van Norman area from such an earthquake are estimated as follows: peak horizontal acceleration of 0.5 g, peak velocity of 1.97 ft/sec (60 cm/sec), displacement of 1.31 ft (40 cm), and duration of shaking at accelerations greater than 0.05 g, 80 sec. The permanent effects of the expectable local earthquake could include simultaneous fault movement at the lower damsite, the upper damsite, and the site proposed for a replacement dam halfway between the upper and lower dams. The maximum differential displacements due to such movements are estimated at 16.4 ft (5 m) at the lower damsite and about 9.6 ft (2.93 m) at the upper and proposed damsites. The 1971 San Fernando earthquake (M 6?) was accompanied by the most intense ground motions ever recorded instrumentally for a natural earthquake. At the lower Van Norman dam, horizontal accelerations exceeded 0.6 g, and shaking greater than 0.25 g lasted for about 13 see; at Pacoima dam, 6 mi (10 km) northeast of the lower dam, high-frequency peak horizontal accelerations of 1.25 g were recorded in two directions, and shaking greater than 0.25 g lasted for about 7 sec. Permanent effects of the earthquake include slope failures in the embankments of the upper

  3. Motion.

    ERIC Educational Resources Information Center

    Gerhart, James B.; Nussbaum, Rudi H.

    This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

  4. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  5. Impact of ground mover motion and windowing on stationary and moving shadows in synthetic aperture radar imagery

    NASA Astrophysics Data System (ADS)

    Miller, J.; Bishop, E.; Doerry, A.; Raynal, A. M.

    2015-05-01

    This paper describes the impact of ground mover motion and windowing on stationary and moving shadows in Synthetic Aperture Radar (SAR) and video SAR mode imagery. The technique provides a foundation for optimizing algorithms that detect ground movers in SAR imagery. The video SAR mode provides a persistent view of a scene centered at the Motion Compensation Point (MCP). The radar platform follows a circular flight path. Detecting a stationary shadow in a SAR image is important because the shadow indicates a detection of an object with a height component near the shadow. Similarly, the detection of a shadow that moves from frame to frame indicates the detection of a ground mover at the location of the moving shadow. An approach analyzes the impact of windowing in calculating the brightness of a pixel in a stationary, finite-sized shadow region. An extension of the approach describes the pixel brightness for a moving shadow as a function of its velocity. The pixel brightness provides an upper bound on the Probability of Detection (PD) and a lower bound on the Probability of False Alarm (PFA) for a finite-sized, stationary or moving shadow in the presence of homogeneous, ideal clutter. Synthetic data provides shadow characteristics for a radar scenario that lend themselves for detecting a ground mover. The paper presents 2011-2014 flight data collected by General Atomics Aeronautical Systems, Inc. (GA-ASI).

  6. Distribution of Ground Motions for the 2008 Mw5.4 Chino Hills Earthquake

    NASA Astrophysics Data System (ADS)

    Yong, A.; Hough, S. E.; Wills, C. J.; Wald, D. J.

    2008-12-01

    The 29 July 2008 Mw5.4 Chino Hills earthquake was widely felt throughout the greater Los Angeles region. Over 40,000 people filled out the Community Internet Intensity Map (CIIM), also known as the "Did You Feel It?" questionnaire, and the ShakeMap for the event is constrained by amplitudes from over 500 stations. The CIIM responses provide Modified Mercalli Intensity (MMI) values for 802 Zip codes. Due to the dense population of the greater Los Angeles region, intensity values averaged within Zip codes provide good spatial correlation to the location of the actual reporting sites. We use a least-squares approach to fit the average MMI to a standard functional form, MMI = A - Br - C log r (where r represents distance from the observation site to the epicenter and A, B and C are constants), and calculate the residuals. The distribution of average intensities clusters closely around the curve of the equation, corroborating the conclusion (e.g., Atkinson and Wald, SRL, 2006) that CIIM intensities provide a consistent measure of earthquake ground motions. A comparison of CIIM intensities and instrumentally determined ShakeMap intensities reveals generally good correspondence, but suggests a tendency for ShakeMap intensities to be higher at basin sites. We conclude that the ShakeMap intensities reflect long-period amplification, whereas observed intensities were more controlled by higher frequency accelerations. Where both the CIIM map and ShakeMap show systematic variations, the distributions show a strong correlation with near-surface geological structure, as well as with basin depth. Our preliminary conclusions are: 1) as expected, intensities are lower at hard rock sites; 2) intensities are systematically higher in the deepest parts of the basin and significantly lower in shallow regions. Intensities are systematically lower to the west of the Newport-Inglewood fault correlating with subtle topographic relief and shallower basin depths; 3) there is a suggestion that

  7. Clastic Pipes: Proxies of High Water Tables and Strong Ground Motion, Jurassic Carmel Formation, Southern Utah

    NASA Astrophysics Data System (ADS)

    Wheatley, David; Chan, Marjorie

    2015-04-01

    Multiple soft sediment deformation features from bed-scale to basin-scale are well preserved within the Jurassic Carmel Formation of Southern Utah. Field mapping reveals thousands of small-scale clastic injectite pipes (10 cm to 10 m diameter, up to 20 m tall) in extremely high densities (up to 500+ pipes per 0.075 square kilometers). The pipes weather out in positive relief from the surrounding host strata of massive sandstone (sabkha) and crossbedded sands with minor conglomerate and shale (fluvial) deposits. The host rock shows both brittle and ductile deformation. Reverse, normal, and antithetical faulting is common with increased frequency, including ring faults, surrounding the pipes. The pipes formed from liquefaction and subsequent fluidization induced by strong ground motion. Down-dropped, graben blocks and ring faults surrounding pipes indicate initial sediment volume increase during pipe emplacement followed by sediment volume decrease during dewatering. Complex crosscutting relationships indicate several injection events where some pipe events reached the surface as sand blows. Multiple ash layers provide excellent stratigraphic and temporal constraints for the pipe system with the host strata deposited between 166 and 164 Ma. Common volcanic fragments and rounded volcanic cobbles occur within sandstone and conglomerate beds, and pipes. Isolated volcanic clasts in massive sandstone indicate explosive volcanic events that could have been the exogenic trigger for earthquakes. The distribution of pipes are roughly parallel to the Middle Jurassic paleoshoreline located in marginal environments between the shallow epicontinental Sundance Sea and continental dryland. At the vertical stratigraphic facies change from dominantly fluvial sediments to dominantly massive sabkha sediments, there is a 1-2 m-thick floodplain mudstone that was a likely seal for underlying, overpressurized sediments. The combination of loose porous sediment at a critical depth of water

  8. Probabilistic Seismic Hazard Maps for Seattle, Washington, Based on 3D Ground-Motion Simulations

    NASA Astrophysics Data System (ADS)

    Frankel, A. D.; Stephenson, W. J.; Carver, D. L.; Williams, R. A.; Odum, J. K.; Rhea, S.

    2007-12-01

    We have produced probabilistic seismic hazard maps for Seattle using over 500 3D finite-difference simulations of ground motions from earthquakes in the Seattle fault zone, Cascadia subduction zone, South Whidbey Island fault, and background shallow and deep source areas. The maps depict 1 Hz response spectral accelerations with 2, 5, and 10% probabilities of being exceeded in 50 years. The simulations were used to generate site and source dependent amplification factors that are applied to rock-site attenuation relations. The maps incorporate essentially the same fault sources and earthquake recurrence times as the 2002 national seismic hazard maps. The simulations included basin surface waves and basin-edge focusing effects from a 3D model of the Seattle basin. The 3D velocity model was validated by modeling several earthquakes in the region, including the 2001 M6.8 Nisqually earthquake, that were recorded by our Seattle Urban Seismic Network and the Pacific Northwest Seismic Network. The simulations duplicate our observation that earthquakes from the south and southwest typically produce larger amplifications in the Seattle basin than earthquakes from other azimuths, relative to rock sites outside the basin. Finite-fault simulations were run for earthquakes along the Seattle fault zone, with magnitudes ranging from 6.6 to 7.2, so that the effects of rupture directivity were included. Nonlinear amplification factors for soft-soil sites of fill and alluvium were also applied in the maps. For the Cascadia subduction zone, 3D simulations with point sources at different locations along the zone were used to determine amplification factors across Seattle expected for great subduction-zone earthquakes. These new urban seismic hazard maps are based on determinations of hazard for 7236 sites with a spacing of 280 m. The maps show that the highest hazard locations for this frequency band (around 1 Hz) are soft-soil sites (fill and alluvium) within the Seattle basin and

  9. CHARACTERIZING THE YUCCA MOUNTAIN SITE FOR DEVELOPING SEISMIC DESIGN GROUND MOTIONS

    SciTech Connect

    S. Upadhyaya, I. Wong, R. Kulkarni, K. Stokoe, M. Dober, W. Silva, and R. Quittmeyer

    2006-02-24

    Yucca Mountain, Nevada is the designated site for the first long-term geologic repository to safely dispose spent nuclear fuel and high-level nuclear waste in the U.S. Yucca Mountain consists of stacked layers of welded and non-welded volcanic tuffs. Site characterization studies are being performed to assess its future performance as a permanent geologic repository. These studies include the characterization of the shear-wave velocity (Vs) structure of the repository block and the surface facilities area. The Vs data are an input in the calculations of ground motions for the preclosure seismic design and for postclosure performance assessment and therefore their accurate estimation is needed. Three techniques have been employed: 24 downhole surveys, 15 suspension seismic logging surveys and 95 spectral-analysis-of-surface-waves (SASW) surveys have been performed to date at the site. The three data sets were compared with one another and with Vs profiles developed from vertical seismic profiling data collected by the Lawrence Berkeley National Laboratory and with Vs profiles developed independently by the University of Nevada, Reno using the refraction microtremor technique. Based on these data, base case Vs profiles have been developed and used in site response analyses. Since the question of adequate sampling arises in site characterization programs and a correlation between geology and Vs would help address this issue, a possible correlation was evaluated. To assess the influence of different factors on velocity, statistical analyses of the Vs data were performed using the method of multi-factor Analysis of Variance (ANOVA). The results of this analysis suggest that the effect of each of three factors, depth, lithologic unit, and spatial location, on velocity is statistically significant. Furthermore, velocity variation with depth is different at different spatial locations: Preliminary results show that the lithologic unit alone explains about 54% and 42% of

  10. Site Transfer Functions of Three-Component Ground Motion in Western Turkey

    NASA Astrophysics Data System (ADS)

    Ozgur Kurtulmus, Tevfik; Akyol, Nihal; Camyildiz, Murat; Gungor, Talip

    2015-04-01

    Because of high seismicity accommodating crustal deformation and deep graben structures, on which have, urbanized and industrialized large cities in western Turkey, the importance of site-specific seismic hazard assessments becomes more crucial. Characterizing source, site and path effects is important for both assessing the seismic hazard in a specific region and generation of the building codes/or renewing previous ones. In this study, we evaluated three-component recordings for micro- and moderate-size earthquakes with local magnitudes ranging between 2.0 and 5.6. This dataset is used for site transfer function estimations, utilizing two different spectral ratio approaches 'Standard Spectral Ratio-(SSR)' and 'Horizontal to Vertical Spectral Ratio-(HVSR)' and a 'Generalized Inversion Technique-(GIT)' to highlight site-specific seismic hazard potential of deep basin structures of the region. Obtained transfer functions revealed that the sites located near the basin edges are characterized by broader HVSR curves. Broad HVSR peaks could be attributed to the complexity of wave propagation related to significant 2D/3D velocity variations at the sediment-bedrock interface near the basin edges. Comparison of HVSR and SSR estimates for the sites located on the grabens showed that SSR estimates give larger values at lower frequencies which could be attributed to lateral variations in regional velocity and attenuation values caused by basin geometry and edge effects. However, large amplitude values of vertical component GIT site transfer functions were observed at varying frequency ranges for some of the stations. These results imply that vertical component of ground motion is not amplification free. Contamination of HVSR site transfer function estimates at different frequency bands could be related to complexities in the wave field caused by deep or shallow heterogeneities in the region such as differences in the basin geometries, fracturing and fluid saturation along

  11. The strong ground motion in Mexico City: array and borehole data analysis.

    NASA Astrophysics Data System (ADS)

    Roullé, A.; Chávez-García, F. J.

    2003-04-01

    1994 by a temporal dense network installed in the firm rock zone of Mexico City were analysed using the same techniques. The results confirm the presence of a diffracting zone south of the valley. These results confirm the hypothesis of a possible interaction between the soft clay layers resonance and diffracted wavetrains of Rayleigh waves to explain both the amplification and the long duration of strong ground motion in Mexico City.

  12. Sensitivity of ground motion parameters to local site effects for areas characterised by a thick buried low-velocity layer.

    NASA Astrophysics Data System (ADS)

    Farrugia, Daniela; Galea, Pauline; D'Amico, Sebastiano; Paolucci, Enrico

    2016-04-01

    It is well known that earthquake damage at a particular site depends on the source, the path that the waves travel through and the local geology. The latter is capable of amplifying and changing the frequency content of the incoming seismic waves. In regions of sparse or no strong ground motion records, like Malta (Central Mediterranean), ground motion simulations are used to obtain parameters for purposes of seismic design and analysis. As an input to ground motion simulations, amplification functions related to the shallow subsurface are required. Shear-wave velocity profiles of several sites on the Maltese islands were obtained using the Horizontal-to-Vertical Spectral Ratio (H/V), the Extended Spatial Auto-Correlation (ESAC) technique and the Genetic Algorithm. The sites chosen were all characterised by a layer of Blue Clay, which can be up to 75 m thick, underlying the Upper Coralline Limestone, a fossiliferous coarse grained limestone. This situation gives rise to a velocity inversion. Available borehole data generally extends down till the top of the Blue Clay layer therefore the only way to check the validity of the modelled shear-wave velocity profile is through the thickness of the topmost layer. Surface wave methods are characterised by uncertainties related to the measurements and the model used for interpretation. Moreover the inversion procedure is also highly non-unique. Such uncertainties are not commonly included in site response analysis. Yet, the propagation of uncertainties from the extracted dispersion curves to inversion solutions can lead to significant differences in the simulations (Boaga et al., 2011). In this study, a series of sensitivity analyses will be presented with the aim of better identifying those stratigraphic properties which can perturb the ground motion simulation results. The stochastic one-dimensional site response analysis algorithm, Extended Source Simulation (EXSIM; Motazedian and Atkinson, 2005), was used to perform

  13. Multi-Hazard Analysis for the Estimation of Ground Motion Induced by Landslides and Tectonics

    NASA Astrophysics Data System (ADS)

    Iglesias, Rubén; Koudogbo, Fifame; Ardizzone, Francesca; Mondini, Alessandro; Bignami, Christian

    2016-04-01

    Space-borne synthetic aperture radar (SAR) sensors allow obtaining all-day all-weather terrain complex reflectivity images which can be processed by means of Persistent Scatterer Interferometry (PSI) for the monitoring of displacement episodes with extremely high accuracy. In the work presented, different PSI strategies to measure ground surface displacements for multi-scale multi-hazard mapping are proposed in the context of landslides and tectonic applications. This work is developed in the framework of ESA General Studies Programme (GSP). The present project, called Multi Scale and Multi Hazard Mapping Space based Solutions (MEMpHIS), investigates new Earth Observation (EO) methods and new Information and Communications Technology (ICT) solutions to improve the understanding and management of disasters, with special focus on Disaster Risk Reduction rather than Rapid Mapping. In this paper, the results of the investigation on the key processing steps for measuring large-scale ground surface displacements (like the ones originated by plate tectonics or active faults) as well as local displacements at high resolution (like the ones related with active slopes) will be presented. The core of the proposed approaches is based on the Stable Point Network (SPN) algorithm, which is the advanced PSI processing chain developed by ALTAMIRA INFORMATION. Regarding tectonic applications, the accurate displacement estimation over large-scale areas characterized by low magnitude motion gradients (3-5 mm/year), such as the ones induced by inter-seismic or Earth tidal effects, still remains an open issue. In this context, a low-resolution approach based in the integration of differential phase increments of velocity and topographic error (obtained through the fitting of a linear model adjustment function to data) will be evaluated. Data from the default mode of Sentinel-1, the Interferometric Wide Swath Mode, will be considered for this application. Regarding landslides

  14. Modeling Strong Ground Motion during the February 22 2011 M6.3 Christchurch, New Zealand, Earthquake

    NASA Astrophysics Data System (ADS)

    Benites, R. A.; Fry, B.; Kaiser, A. E.

    2012-12-01

    We present a simple, kinematic model of the rupture of the M6.3 February 22 2011 earthquake in the city of Christchurch, New Zealand, that provides insights into the factors influencing observed ground motions. The model is based on a rectangular 8 x 9 km fault dipping 75o, striking 64o and rupturing with a thrust mechanism. The fault is embedded in a velocity model consisting of one layer over a uniform half-space representing the stiffest soil deposit and the bedrock underneath, respectively (Brown, L.J.; Weeber, J.H. 1992). The free-surface of the soil layer is assumed to be flat, however, the bedrock interface (initially at 900 m depth) pinches out as a 3-D cosine shaped free-surface topography up to 250 m high, representing Bank's Peninsula. The base of the topography is elliptical, with principle axes of 9 km and 4.5 km. Numerical modeling of the rupture shows that the observed corresponding strong ground motion is mainly due to two factors: the coherent rupture of a section of the fault, of 25 km2 area, with 116o rake and 3.1 km/s rupture velocity, and the presence of the sediments immediately overlying the fault. The discretization of the whole fault into several subfaults each with prescribed values of slip in the range 0.4-3.0 m, and rise time, allows the parametric study of the ground motion using several rupture scenarios. The model with the coherent rupture described above best reproduces the high (1.2 g -1.8 g) accelerations observed at stations in the footwall of the fault. The incidence upon the topography appears to produce Rayleigh waves propagating away from it. This is in agreement with particle motion surface wave analysis of the measured seismograms that reveals the contribution of Rayleigh wave energy to the observed long-period ground motions. Furthermore, arrival times of the Rayleigh wave energy are consistent with predicted travel times from our basin velocity model. We reproduce prominent near-surface effects at many Christchurch strong

  15. Ground motion simulation for the 23 August 2011, Mineral, Virginia earthquake using physics-based and stochastic broadband methods

    USGS Publications Warehouse

    Sun, Xiaodan; Hartzell, Stephen; Rezaeian, Sanaz

    2015-01-01

    Three broadband simulation methods are used to generate synthetic ground motions for the 2011 Mineral, Virginia, earthquake and compare with observed motions. The methods include a physics‐based model by Hartzell et al. (1999, 2005), a stochastic source‐based model by Boore (2009), and a stochastic site‐based model by Rezaeian and Der Kiureghian (2010, 2012). The ground‐motion dataset consists of 40 stations within 600 km of the epicenter. Several metrics are used to validate the simulations: (1) overall bias of response spectra and Fourier spectra (from 0.1 to 10 Hz); (2) spatial distribution of residuals for GMRotI50 peak ground acceleration (PGA), peak ground velocity, and pseudospectral acceleration (PSA) at various periods; (3) comparison with ground‐motion prediction equations (GMPEs) for the eastern United States. Our results show that (1) the physics‐based model provides satisfactory overall bias from 0.1 to 10 Hz and produces more realistic synthetic waveforms; (2) the stochastic site‐based model also yields more realistic synthetic waveforms and performs superiorly for frequencies greater than about 1 Hz; (3) the stochastic source‐based model has larger bias at lower frequencies (<0.5  Hz) and cannot reproduce the varying frequency content in the time domain. The spatial distribution of GMRotI50 residuals shows that there is no obvious pattern with distance in the simulation bias, but there is some azimuthal variability. The comparison between synthetics and GMPEs shows similar fall‐off with distance for all three models, comparable PGA and PSA amplitudes for the physics‐based and stochastic site‐based models, and systematic lower amplitudes for the stochastic source‐based model at lower frequencies (<0.5  Hz).

  16. Identifying the unique ground motion signatures of supershear earthquakes - The one-two punch effect on high-rise buildings

    NASA Astrophysics Data System (ADS)

    Rosakis, A.; Mello, M.; Bhat, H.; Krishnan, S.; Kanamori, H.

    2011-12-01

    Directly studying earthquakes presents a host of insurmountable difficulties, the least of which is our inability to trigger earthquakes of various magnitudes at will and the lack of means of scrutinizing the behavior at depth while the quake propagates. We have developed techniques to produce miniature (or surrogate) laboratory earthquakes and follow their progress with high-speed imaging tools. Our laboratory quakes mimic actual ones, and have allowed us to demonstrate the existence of ruptures of super-shear or intersonic rupture speeds. The propagating fronts of such supershear ruptures feature a Mach-cone of shear shock waves similar to that of supersonic aircraft. For earthquake ruptures transitioning from sub-Rayleigh to supershear rupture speeds, this unusual shear Mach cone feature is also followed by a trailing Rayleigh disturbance which is all that remains of the old sub-Rayleigh rupture after transition is complete. Each propagating disturbance contributes to the unique ground motion signature in the near field. We refer to this as a one-two punch scenario. In particular, ground motion associated with passage of the shear Mach features a dominant fault-parallel velocity component while ground motion from the trailing Rayleigh field is characterized by a dominant fault-normal velocity component (characteristic of common, sub-shear earthquake ruptures). Appropriate scaling of the laboratory ground velocity measurements are used to shake 3-D numerical models of high-rise buildings (located in near fault locations) with hypothetical supershear and sub-Rayleigh earthquakes with unexpected implication to building safety and seismic hazard analysis.

  17. Ground motion modeling for the 6 April 2009 earthquake (MW 6.3) at Poggio Picenze (central Italy)

    NASA Astrophysics Data System (ADS)

    Costanzo, M. R.; Nunziata, C.

    2015-04-01

    The town of Poggio Picenze (central Italy), located ~12 km SE of L'Aquila, reported a damage intensity of VIII-IX (MCS) for the 6 April 2009 (MW = 6.3) earthquake. In the following days, two stations (M128 and PGG) were operating in the historical centre and recorded several aftershocks. The aim of this paper is to model ground motion at Poggio Picenze for the 6 April 2009 earthquake. First, recordings of 16 aftershocks (2.0 ≤ ML ≤ 4.2), located in the epicentral area of the strong event, are processed to define average shear wave velocity (VS) profiles with depth through the non-linear inversion of Rayleigh wave group velocity dispersion curves of the fundamental mode extracted with the frequency-time analysis. Then, the local average VS model and the regional model, in addition to two shallow downhole measurements, are used to define two 2-D cross-sections passing through the seismic stations. Ground motion is modeled along such cross-sections for the strongest aftershock (ML = 4.2) with the hybrid method consisting of modal summation and finite difference algorithms. Once the modeling results at the M128 and PGG stations are validated, the ground motion is computed for the main shock. Spectral amplifications up to factors 5-6 are estimated at 3-4 Hz for the vertical component and up to factors 2-3 at 2-6 Hz for the radial and transverse components. Ground accelerations are maximum in the horizontal plane, along the transverse component (around 0.4 g) and are half along the vertical component.

  18. Seismic fragility analysis of typical pre-1990 bridges due to near- and far-field ground motions

    NASA Astrophysics Data System (ADS)

    Mosleh, Araliya; Razzaghi, Mehran S.; Jara, José; Varum, Humberto

    2016-03-01

    Bridge damages during the past earthquakes caused several physical and economic impacts to transportation systems. Many of the existing bridges in earthquake prone areas are pre-1990 bridges and were designed with out of date regulation codes. The occurrences of strong motions in different parts of the world show every year the vulnerability of these structures. Nonlinear dynamic time history analyses were conducted to assess the seismic vulnerability of typical pre-1990 bridges. A family of existing concrete bridge representative of the most common bridges in the highway system in Iran is studied. The seismic demand consists in a set of far-field and near-field strong motions to evaluate the likelihood of exceeding the seismic capacity of the mentioned bridges. The peak ground accelerations (PGAs) were scaled and applied incrementally to the 3D models to evaluate the seismic performance of the bridges. The superstructure was assumed to remain elastic and the nonlinear behavior in piers was modeled by assigning plastic hinges in columns. In this study the displacement ductility and the PGA are selected as a seismic performance indicator and intensity measure, respectively. The results show that pre-1990 bridges subjected to near-fault ground motions reach minor and moderate damage states.

  19. Physics-based Broadband Ground Motion Simulations for Probable M>7.0 earthquakes in the Marmara Sea Region (Turkey)

    NASA Astrophysics Data System (ADS)

    Akinci, Aybige; Aochi, Hideo; Herrero, Andre; Pischiutta, Marta; Karanikas, Dimitris

    2016-04-01

    The city of Istanbul is characterized by one of the highest levels of seismic risk in Europe and the Mediterranean region. The important source of the increased risk in Istanbul is the remarkable probability of the occurrence of a large earthquake, which stands at about 65% during the coming years due to the existing seismic gap and the post-1999 earthquake stress transfer at the western portion of the North Anatolian Fault Zone (NAFZ). In this study, we have simulated hybrid broadband time histories from two selected scenario earthquakes having magnitude M>7.0 in the Marmara Sea within 10-20 km of Istanbul believed to have generated devastating 1509 event in the region. The physics-based rupture scenarios, which may be an indication of potential future events, are adopted to estimate the ground motion characteristics and its variability in the region. Two simulation techniques (a full 3D wave propagation method to generate low-frequency seismograms, <~1 Hz and a stochastic technique to simulate high-frequency seismograms, >1Hz) are used to compute more realistic time series associated with scenario earthquakes having magnitudes Mw >7.0 in the Marmara Sea Region. A dynamic rupture is generated and computed with a boundary integral equation method and the propagation in the medium is realized through a finite difference approach (Aochi and Ulrich, 2015). The high frequency radiation is computed using stochastic finite-fault model approach based on a dynamic corner frequency (Motazedian and Atkinson, 2005; Boore, 2009). The results from the two simulation techniques are then merged by performing a weighted summation at intermediate frequencies to calculate broadband synthetic time series. The hybrid broadband ground motions computed with the proposed approach are validated by comparing peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration (SA) with recently proposed ground motion prediction equations (GMPE) in the region. Our

  20. 3-D ground motion modeling for M7 dynamic rupture earthquake scenarios on the Wasatch fault, Utah

    NASA Astrophysics Data System (ADS)

    Roten, D.; Olsen, K. B.; Cruz Atienza, V. M.; Pechmann, J. C.; Magistrale, H. W.

    2009-12-01

    The Salt Lake City segment of the Wasatch fault (WFSLC), located on the eastern edge of the Salt Lake Basin (SLB), is capable of producing M7 earthquakes and represents a serious seismic hazard to Salt Lake City, Utah. We simulate a series of rupture scenarios on the WFSLC to quantify the ground motion expected from such M7 events and to assess the importance of amplification effects from basin focusing and source directivity. We use the newly revised Wasatch Front community velocity model for our simulations, which is tested by simulating records of three local Mw 3.3-3.7 earthquakes in the frequency band 0.5 to 1.0 Hz. The M7 earthquake scenarios make use of a detailed 3-D model geometry of the WFSLC that we developed based on geological observations. To obtain a suite of realistic source representations for M7 WFSLC simulations we perform spontaneous-rupture simulations on a planar 43 km by 23 km fault with the staggered-grid split-node finite-difference (FD) method. We estimate the initial distribution of shear stress using models that assume depth-dependent normal stress for a dipping, normal fault as well as simpler models which use constant (depth-independent) normal stress. The slip rate histories from the spontaneous rupture scenarios are projected onto the irregular dipping geometry of the WFSLC and used to simulate 0-1 Hz wave propagation in the SLB area using a 4th-order, staggered-grid visco-elastic FD method. We find that peak ground velocities tend to be larger on the low-velocity sediments on the hanging wall side of the fault than on outcropping rock on the footwall side, confirming results of previous studies on normal faulting earthquakes. The simulated ground motions reveal strong along-strike directivity effects for ruptures nucleating towards the ends of the WFSLC. The 0-1 Hz FD simulations are combined with local scattering operators to obtain broadband (0-10 Hz) synthetics and maps of average peak ground motions. Finally we use broadband

  1. Dynamic modeling of injection-induced fault reactivation and ground motion and impact on surface structures and human perception

    SciTech Connect

    Rutqvist, Jonny; Cappa, Frederic; Rinaldi, Antonio P.; Godano, Maxime

    2014-12-31

    We summarize recent modeling studies of injection-induced fault reactivation, seismicity, and its potential impact on surface structures and nuisance to the local human population. We used coupled multiphase fluid flow and geomechanical numerical modeling, dynamic wave propagation modeling, seismology theories, and empirical vibration criteria from mining and construction industries. We first simulated injection-induced fault reactivation, including dynamic fault slip, seismic source, wave propagation, and ground vibrations. From co-seismic average shear displacement and rupture area, we determined the moment magnitude to about Mw = 3 for an injection-induced fault reactivation at a depth of about 1000 m. We then analyzed the ground vibration results in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and frequency content, with comparison to the U.S. Bureau of Mines’ vibration criteria for cosmetic damage to buildings, as well as human-perception vibration limits. For the considered synthetic Mw = 3 event, our analysis showed that the short duration, high frequency ground motion may not cause any significant damage to surface structures, and would not cause, in this particular case, upward CO2 leakage, but would certainly be felt by the local population.

  2. Dynamic modeling of injection-induced fault reactivation and ground motion and impact on surface structures and human perception

    DOE PAGESBeta

    Rutqvist, Jonny; Cappa, Frederic; Rinaldi, Antonio P.; Godano, Maxime

    2014-12-31

    We summarize recent modeling studies of injection-induced fault reactivation, seismicity, and its potential impact on surface structures and nuisance to the local human population. We used coupled multiphase fluid flow and geomechanical numerical modeling, dynamic wave propagation modeling, seismology theories, and empirical vibration criteria from mining and construction industries. We first simulated injection-induced fault reactivation, including dynamic fault slip, seismic source, wave propagation, and ground vibrations. From co-seismic average shear displacement and rupture area, we determined the moment magnitude to about Mw = 3 for an injection-induced fault reactivation at a depth of about 1000 m. We then analyzed themore » ground vibration results in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and frequency content, with comparison to the U.S. Bureau of Mines’ vibration criteria for cosmetic damage to buildings, as well as human-perception vibration limits. For the considered synthetic Mw = 3 event, our analysis showed that the short duration, high frequency ground motion may not cause any significant damage to surface structures, and would not cause, i